Kindia ( N’ko : ߞߌ߲ߘߌߦߊ߫) is the fourth largest city in Guinea , located about 85 miles (137 km) northeast of the nation's capital, Conakry . Its estimated population in 2008 was 181,126. Kindia serves as the capital and largest city of Kindia Prefecture and Kindia Region . It also functions as a sub-prefecture of Guinea.
101-597: The city is near Mount Gangan and the Mariée Falls . The city was founded in 1904 on the route of Conakry Railway in Kankan. Kindia grew around banana plantations following the construction of a now-closed railway to the capital. The city of Kindia has an ethnically diverse population, although the Susu make up the majority of the population, followed by the Mandinka . The city
202-409: A Pneumocystis carinii infection, which indicates a weak immune system. Triploidy may be the result of either digyny (the extra haploid set is from the mother) or diandry (the extra haploid set is from the father). Diandry is mostly caused by reduplication of the paternal haploid set from a single sperm, but may also be the consequence of dispermic (two sperm) fertilization of the egg. Digyny
303-626: A hybrid genome with two sets of chromosomes derived from Triticum urartu and two sets of chromosomes derived from Aegilops speltoides . Each chromosome pair derived from the Triticum urartu parent is homoeologous to the opposite chromosome pair derived from the Aegilops speltoides parent, though each chromosome pair unto itself is homologous . Examples in animals are more common in non-vertebrates such as flatworms , leeches , and brine shrimp . Within vertebrates, examples of stable polyploidy include
404-410: A miscarriage ; those that do survive to term typically die shortly after birth. In some cases, survival past birth may be extended if there is mixoploidy with both a diploid and a triploid cell population present. There has been one report of a child surviving to the age of seven months with complete triploidy syndrome. He failed to exhibit normal mental or physical neonatal development, and died from
505-423: A banana plant is mature, the corm stops producing new leaves and begins to form a flower spike or inflorescence . A stem develops which grows up inside the pseudostem, carrying the immature inflorescence until eventually it emerges at the top. Each pseudostem normally produces a single inflorescence, also known as the "banana heart". After fruiting, the pseudostem dies, but offshoots will normally have developed from
606-477: A few days, the fruit begins to ripen and is distributed for final sale. Ripe bananas can be held for a few days at home. If bananas are too green, they can be put in a brown paper bag with an apple or tomato overnight to speed up the ripening process. The excessive use of fertilizers contributes greatly to eutrophication in streams and lakes, harming aquatic life, while expanding banana production has led to deforestation. As soil nutrients are depleted, more forest
707-461: A hybrid- polyploid complex; hybrids can be diploid, triploid, tetraploid, or pentaploid, i.e. they may have 2, 3, 4, or 5 sets of chromosomes . This makes them difficult to breed as hybrids are often sterile, in addition to the challenge of breeding seedless (parthenocarpic) varieties. The Honduran Foundation for Agricultural Research has bred a seedless banana that is resistant to both Panama disease and black Sigatoka disease. The team made use of
808-498: A lesser extent to make banana paper and textiles , while some are grown as ornamental plants . The world's largest producers of bananas in 2022 were India and China, which together accounted for approximately 26% of total production. Bananas are eaten raw or cooked in recipes varying from curries to banana chips , fritters , fruit preserves, or simply baked or steamed. Worldwide, there is no sharp distinction between dessert "bananas" and cooking "plantains": this works well enough in
909-846: A mechanism for a kind of 'reverse speciation', whereby gene flow is enabled following the polyploidy event, even between lineages that previously experienced no gene flow as diploids. This has been detailed at the genomic level in Arabidopsis arenosa and Arabidopsis lyrata . Each of these species experienced independent autopolyploidy events (within-species polyploidy, described below), which then enabled subsequent interspecies gene flow of adaptive alleles, in this case stabilising each young polyploid lineage. Such polyploidy-enabled adaptive introgression may allow polyploids at act as 'allelic sponges', whereby they accumulate cryptic genomic variation that may be recruited upon encountering later environmental challenges. Polyploid types are labeled according to
1010-481: A more common path to allopolyploidy because F 1 hybrids between taxa often have relatively high rates of unreduced gamete formation – divergence between the genomes of the two taxa result in abnormal pairing between homoeologous chromosomes or nondisjunction during meiosis. In this case, allopolyploidy can actually restore normal, bivalent meiotic pairing by providing each homoeologous chromosome with its own homologue. If divergence between homoeologous chromosomes
1111-546: A much wider range of cultivars than large commercial plantations do, and in Southeast Asia—the center of diversity for bananas, both wild and cultivated—the distinction between "bananas" and "plantains" does not work. Many bananas are used both raw and cooked. There are starchy cooking bananas which are smaller than those eaten raw. The range of colors, sizes and shapes is far wider than in those grown or sold in Africa, Europe or
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#17328549569791212-403: A paleopolyploid. It is a middle aged polyploid. Often this refers to whole genome duplication followed by intermediate levels of diploidization. Ancient genome duplications probably occurred in the evolutionary history of all life. Duplication events that occurred long ago in the history of various evolutionary lineages can be difficult to detect because of subsequent diploidization (such that
1313-695: A polyploid starts to behave cytogenetically as a diploid over time) as mutations and gene translations gradually make one copy of each chromosome unlike the other copy. Over time, it is also common for duplicated copies of genes to accumulate mutations and become inactive pseudogenes. In many cases, these events can be inferred only through comparing sequenced genomes . Examples of unexpected but recently confirmed ancient genome duplications include baker's yeast ( Saccharomyces cerevisiae ), mustard weed/thale cress ( Arabidopsis thaliana ), rice ( Oryza sativa ), and two rounds of whole genome duplication (the 2R hypothesis ) in an early evolutionary ancestor of
1414-461: A problematic issue for taxonomists. Linnaeus originally placed bananas into two species based only on their uses as food: Musa sapientum for dessert bananas and Musa paradisiaca for plantains . More species names were added, but this approach proved to be inadequate for the number of cultivars in the primary center of diversity of the genus, Southeast Asia. Many of these cultivars were given names that were later discovered to be synonyms . In
1515-470: A series of papers published from 1947 onward, Ernest Cheesman showed that Linnaeus's Musa sapientum and Musa paradisiaca were cultivars and descendants of two wild seed-producing species, Musa acuminata and Musa balbisiana , both first described by Luigi Aloysius Colla . Cheesman recommended the abolition of Linnaeus's species in favor of reclassifying bananas according to three morphologically distinct groups of cultivars – those primarily exhibiting
1616-579: A sterile triploid hybrid between E. guttata and E. lutea, both of which have been introduced and naturalised in the United Kingdom. New populations of E. peregrina arose on the Scottish mainland and the Orkney Islands via genome duplication from local populations of E. × robertsii . Because of a rare genetic mutation, E. peregrina is not sterile. On the other hand, polyploidization can also be
1717-415: A wide variety of soils, as long as it is at least 60 centimetres (2.0 ft) deep, has good drainage and is not compacted. They are fast-growing plants, with a growth rate of up to 1.6 metres (5.2 ft) per day. The leaves of banana plants are composed of a stalk ( petiole ) and a blade ( lamina ). The base of the petiole widens to form a sheath; the tightly packed sheaths make up the pseudostem, which
1818-744: A wild banana of Arunachal Pradesh , India Musa balbisiana , Plantain of South, East, and Southeast Asia Musa x troglodytarum , Fe'i banana of French Polynesia Musa maclayi of Papua New Guinea and Solomon Islands Musa textilis , Abacá or Manila hemp of the Philippines Musa beccarii , a wild banana of Sabah Musa coccinea , Scarlet banana of China and Vietnam Musella lasiocarpa , Golden lotus banana of China Ensete ventricosum , Enset or false banana of Africa Work by Li and colleagues in 2024 identifies three subspecies of M. acuminata , namely sspp. banksii , malaccensis , and zebrina , as contributing substantially to
1919-567: Is all that supports the plant. The edges of the sheath meet when it is first produced, making it tubular. As new growth occurs in the centre of the pseudostem, the edges are forced apart. Cultivated banana plants vary in height depending on the variety and growing conditions. Most are around 5 m (16 ft) tall, with a range from ' Dwarf Cavendish ' plants at around 3 m (10 ft) to ' Gros Michel ' at 7 m (23 ft) or more. Leaves are spirally arranged and may grow 2.7 metres (8.9 ft) long and 60 cm (2.0 ft) wide. When
2020-410: Is allowed to produce two shoots at a time; a larger one for immediate fruiting and a smaller "sucker" or "follower" to produce fruit in 6–8 months. As a non-seasonal crop, bananas are available fresh year-round. They are grown in some 135 countries. In global commerce in 2009, by far the most important cultivars belonged to the triploid Musa acuminata AAA group of Cavendish group bananas. Disease
2121-429: Is cleared for plantations. This causes soil erosion and increases the frequency of flooding. Voluntary sustainability standards such as Rainforest Alliance and Fairtrade are being used to address some of these issues. Banana production certified in this way grew rapidly at the start of the 21st century to represent 36% of banana exports by 2016. However, such standards are applied mainly in countries which focus on
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#17328549569792222-407: Is common among ferns and flowering plants (see Hibiscus rosa-sinensis ), including both wild and cultivated species . Wheat , for example, after millennia of hybridization and modification by humans, has strains that are diploid (two sets of chromosomes), tetraploid (four sets of chromosomes) with the common name of durum or macaroni wheat, and hexaploid (six sets of chromosomes) with
2323-399: Is conserved in multiple gene banks around the world. The banana plant is the largest herbaceous flowering plant. All the above-ground parts of a banana plant grow from a structure called a corm . Plants are normally tall and fairly sturdy with a treelike appearance, but what appears to be a trunk is actually a pseudostem composed of multiple leaf-stalks ( petioles ). Bananas grow in
2424-446: Is dotted by past and recent whole-genome duplication events (see Albertin and Marullo 2012 for review). Several examples of polyploids are known: In addition, polyploidy is frequently associated with hybridization and reticulate evolution that appear to be highly prevalent in several fungal taxa. Indeed, homoploid speciation (hybrid speciation without a change in chromosome number) has been evidenced for some fungal species (such as
2525-698: Is even across the two subgenomes, this can theoretically result in rapid restoration of bivalent pairing and disomic inheritance following allopolyploidization. However multivalent pairing is common in many recently formed allopolyploids, so it is likely that the majority of meiotic stabilization occurs gradually through selection. Because pairing between homoeologous chromosomes is rare in established allopolyploids, they may benefit from fixed heterozygosity of homoeologous alleles. In certain cases, such heterozygosity can have beneficial heterotic effects, either in terms of fitness in natural contexts or desirable traits in agricultural contexts. This could partially explain
2626-885: Is frequent in plants, some estimates suggesting that 30–80% of living plant species are polyploid, and many lineages show evidence of ancient polyploidy ( paleopolyploidy ) in their genomes. Huge explosions in angiosperm species diversity appear to have coincided with the timing of ancient genome duplications shared by many species. It has been established that 15% of angiosperm and 31% of fern speciation events are accompanied by ploidy increase. Polyploid plants can arise spontaneously in nature by several mechanisms, including meiotic or mitotic failures, and fusion of unreduced (2 n ) gametes. Both autopolyploids (e.g. potato ) and allopolyploids (such as canola, wheat and cotton) can be found among both wild and domesticated plant species. Most polyploids display novel variation or morphologies relative to their parental species, that may contribute to
2727-495: Is haploid, and produces gametes by mitosis ; the sporophyte generation is diploid and produces spores by meiosis . Polyploidy is the result of whole-genome duplication during the evolution of species. It may occur due to abnormal cell division , either during mitosis, or more commonly from the failure of chromosomes to separate during meiosis or from the fertilization of an egg by more than one sperm. In addition, it can be induced in plants and cell cultures by some chemicals:
2828-626: Is home to virtually all of the country's ethnic groups. After the capital Conakry, Kindia is home to the second largest Sierra Leonean community in Guinea. An estimated 9,000 Sierra Leoneans reside in the city, many of them have obtain Guinean citizenship. Like every city in Western Guinea, including the capital Conakry, the Susu language is the most widely spoken language in Kindia and is understood by virtually
2929-680: Is included in Ibn al-'Awwam 's 12th-century agricultural work, Kitāb al-Filāḥa ( Book on Agriculture ). During the Middle Ages, bananas from Granada were considered among the best in the Arab world. Bananas were certainly grown in the Christian Kingdom of Cyprus by the late medieval period. Writing in 1458, the Italian traveller and writer Gabriele Capodilista wrote favourably of the extensive farm produce of
3030-415: Is inherited paternally. This facilitates taxonomic study of species and subspecies relationships. In regions such as North America and Europe, Musa fruits offered for sale can be divided into small sweet "bananas" eaten raw when ripe as a dessert, and large starchy "plantains" or cooking bananas , which do not have to be ripe. Linnaeus made this distinction when naming two "species" of Musa . Members of
3131-514: Is more rarely diagnosed than triploidy, but is observed in 1–2% of early miscarriages. However, some tetraploid cells are commonly found in chromosome analysis at prenatal diagnosis and these are generally considered 'harmless'. It is not clear whether these tetraploid cells simply tend to arise during in vitro cell culture or whether they are also present in placental cells in vivo . There are, at any rate, very few clinical reports of fetuses/infants diagnosed with tetraploidy mosaicism. Mixoploidy
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3232-473: Is most commonly caused by either failure of one meiotic division during oogenesis leading to a diploid oocyte or failure to extrude one polar body from the oocyte . Diandry appears to predominate among early miscarriages , while digyny predominates among triploid zygotes that survive into the fetal period. However, among early miscarriages, digyny is also more common in those cases less than 8 + 1 ⁄ 2 weeks gestational age or those in which an embryo
3333-433: Is most commonly induced by treating seeds with the chemical colchicine . Some crops are found in a variety of ploidies: tulips and lilies are commonly found as both diploid and triploid; daylilies ( Hemerocallis cultivars) are available as either diploid or tetraploid; apples and kinnow mandarins can be diploid, triploid, or tetraploid. Besides plants and animals, the evolutionary history of various fungal species
3434-623: Is often associated with apomictic mating systems. In agricultural systems, autotriploidy can result in seedlessness, as in watermelons and bananas . Triploidy is also utilized in salmon and trout farming to induce sterility. Rarely, autopolyploids arise from spontaneous, somatic genome doubling, which has been observed in apple ( Malus domesticus ) bud sports . This is also the most common pathway of artificially induced polyploidy, where methods such as protoplast fusion or treatment with colchicine , oryzalin or mitotic inhibitors are used to disrupt normal mitotic division, which results in
3535-440: Is part of cytology and, more specifically, cytogenetics . Although the replication and transcription of DNA is highly standardized in eukaryotes , the same cannot be said for their karyotypes, which are highly variable between species in chromosome number and in detailed organization despite being constructed out of the same macromolecules. In some cases, there is even significant variation within species. This variation provides
3636-435: Is present. There are also two distinct phenotypes in triploid placentas and fetuses that are dependent on the origin of the extra haploid set. In digyny, there is typically an asymmetric poorly grown fetus , with marked adrenal hypoplasia and a very small placenta . In diandry, a partial hydatidiform mole develops. These parent-of-origin effects reflect the effects of genomic imprinting . Complete tetraploidy
3737-412: Is quite commonly observed in human preimplantation embryos and includes haploid/diploid as well as diploid/tetraploid mixed cell populations. It is unknown whether these embryos fail to implant and are therefore rarely detected in ongoing pregnancies or if there is simply a selective process favoring the diploid cells. A polyploidy event occurred within the stem lineage of the teleost fish. Polyploidy
3838-624: Is the Coast Redwood Sequoia sempervirens , which is a hexaploid (6 x ) with 66 chromosomes (2 n = 6 x = 66), although the origin is unclear. Aquatic plants, especially the Monocotyledons , include a large number of polyploids. The induction of polyploidy is a common technique to overcome the sterility of a hybrid species during plant breeding. For example, triticale is the hybrid of wheat ( Triticum turgidum ) and rye ( Secale cereale ). It combines sought-after characteristics of
3939-533: Is threatening the production of the Cavendish banana worldwide. It is unclear if any existing cultivar can replace Cavendish bananas, so various hybridisation and genetic engineering programs are attempting to create a disease-resistant, mass-market banana. One such strain that has emerged is the Taiwanese Cavendish or Formosana. Export bananas are picked green, and ripened in special rooms upon arrival in
4040-551: Is under- or over-represented are said to be aneuploid (from the Greek words meaning "not", "good", and "fold"). Aneuploidy refers to a numerical change in part of the chromosome set, whereas polyploidy refers to a numerical change in the whole set of chromosomes. Polyploidy occurs in some tissues of animals that are otherwise diploid, such as human muscle tissues. This is known as endopolyploidy . Species whose cells do not have nuclei, that is, prokaryotes , may be polyploid, as seen in
4141-637: Is variable in size, color and firmness, but is usually elongated and curved, with soft flesh rich in starch covered with a peel , which may have a variety of colors when ripe. It grows upward in clusters near the top of the plant. Almost all modern edible seedless ( parthenocarp ) cultivated bananas come from two wild species – Musa acuminata and Musa balbisiana , or hybrids of them. Musa species are native to tropical Indomalaya and Australia ; they were probably domesticated in New Guinea . They are grown in 135 countries, primarily for their fruit, and to
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4242-630: The Ban , Dh , and Ze subgenomes of triploid cultivated bananas respectively. The genus Musa was created by Carl Linnaeus in 1753. The name may be derived from Antonius Musa , physician to the Emperor Augustus , or Linnaeus may have adapted the Arabic word for banana, mauz . The ultimate origin of musa may be in the Trans–New Guinea languages , which have words similar to "#muku"; from there
4343-410: The banana heart , in a large hanging cluster called a bunch , made up of around nine tiers called hands , with up to 20 fruits to a hand. A bunch can weigh 22–65 kilograms (49–143 lb). The stalk ends of the fruits connect up to the rachis part of the inflorescence. Opposite the stalk end, is the blossom end, where the remnants of the flower deviate the texture from the rest of the flesh inside
4444-546: The basidiomycota Microbotryum violaceum ). As for plants and animals, fungal hybrids and polyploids display structural and functional modifications compared to their progenitors and diploid counterparts. In particular, the structural and functional outcomes of polyploid Saccharomyces genomes strikingly reflect the evolutionary fate of plant polyploid ones. Large chromosomal rearrangements leading to chimeric chromosomes have been described, as well as more punctual genetic modifications such as gene loss. The homoealleles of
4545-664: The salmonids and many cyprinids (i.e. carp ). Some fish have as many as 400 chromosomes. Polyploidy also occurs commonly in amphibians; for example the biomedically important genus Xenopus contains many different species with as many as 12 sets of chromosomes (dodecaploid). Polyploid lizards are also quite common. Most are sterile and reproduce by parthenogenesis ; others, like Liolaemus chiliensis , maintain sexual reproduction. Polyploid mole salamanders (mostly triploids) are all female and reproduce by kleptogenesis , "stealing" spermatophores from diploid males of related species to trigger egg development but not incorporating
4646-420: The vertebrates (which includes the human lineage) and another near the origin of the teleost fishes . Angiosperms ( flowering plants ) have paleopolyploidy in their ancestry. All eukaryotes probably have experienced a polyploidy event at some point in their evolutionary history. A karyotype is the characteristic chromosome complement of a eukaryote species . The preparation and study of karyotypes
4747-619: The " plantain subgroup " of banana cultivars, most important as food in West Africa and Latin America, correspond to this description, having long pointed fruit. They are described by Ploetz et al. as "true" plantains, distinct from other cooking bananas. The cooking bananas of East Africa belong to a different group, the East African Highland bananas . Further, small farmers in Colombia grow
4848-637: The 16th century. Southeast Asian banana cultivars, as well as abaca grown for fibers, were introduced to North and Central America by the Spanish from the Philippines, via the Manila galleons . In the 15th and 16th centuries, Portuguese colonists started banana plantations in the Atlantic Islands, Brazil, and western Africa. North Americans began consuming bananas on a small scale at very high prices shortly after
4949-649: The Americas and Europe, but it breaks down in Southeast Asia where many more kinds of bananas are grown and eaten. The term "banana" is applied also to other members of the genus Musa , such as the scarlet banana ( Musa coccinea ), the pink banana ( Musa velutina ), and the Fe'i bananas . Members of the genus Ensete , such as the snow banana ( Ensete glaucum ) and the economically important false banana ( Ensete ventricosum ) of Africa are sometimes included. Both genera are in
5050-812: The Americas. Southeast Asian languages do not make the distinction between "bananas" and "plantains" that is made in English. Thus both Cavendish dessert bananas and Saba cooking bananas are called pisang in Malaysia and Indonesia, kluai in Thailand and chuối in Vietnam. Fe'i bananas , grown and eaten in the islands of the Pacific, are derived from a different wild species. Most Fe'i bananas are cooked, but Karat bananas , which are short and squat with bright red skins, are eaten raw. The earliest domestication of bananas ( Musa spp.)
5151-498: The Caribbean produce bananas for the world market, often alongside other crops. In many tropical countries, the main cultivars produce green (unripe) bananas used for cooking . Because bananas and plantains produce fruit year-round, they provide a valuable food source during the hunger season between harvests of other crops, and are thus important for global food security . Bananas are propagated asexually from offshoots. The plant
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#17328549569795252-646: The Civil War, though it was only in the 1880s that the food became more widespread. As late as the Victorian Era , bananas were not widely known in Europe, although they were available. The earliest modern plantations originated in Jamaica and the related Western Caribbean Zone , including most of Central America . Plantation cultivation involved the combination of modern transportation networks of steamships and railroads with
5353-634: The Indian subcontinent. Some evidence suggests bananas were known to the Indus Valley civilisation from phytoliths recovered from the Kot Diji archaeological site in Pakistan. Southeast Asia remains the region of primary diversity of the banana. Areas of secondary diversity are found in Africa, indicating a long history of banana cultivation there. The banana may have been present in isolated locations elsewhere in
5454-609: The Middle East on the eve of Islam . The spread of Islam was followed by far-reaching diffusion. There are numerous references to it in Islamic texts (such as poems and hadiths ) beginning in the 9th century. By the 10th century, the banana appeared in texts from Palestine and Egypt. From there it diffused into North Africa and Muslim Iberia during the Arab Agricultural Revolution . An article on banana tree cultivation
5555-717: The Philippines, Nigeria and Ecuador. As reported for 2013, total world exports were 20 million tonnes of bananas and 859,000 tonnes of plantains. Ecuador and the Philippines were the leading exporters with 5.4 and 3.3 million tonnes, respectively, and the Dominican Republic was the leading exporter of plantains with 210,350 tonnes. Triploid Polyploidy is a condition in which the cells of an organism have more than two paired sets of ( homologous ) chromosomes . Most species whose cells have nuclei ( eukaryotes ) are diploid , meaning they have two complete sets of chromosomes, one from each of two parents; each set contains
5656-425: The agamic complexes of Crepis . Some plants are triploid. As meiosis is disturbed, these plants are sterile, with all plants having the same genetic constitution: Among them, the exclusively vegetatively propagated saffron crocus ( Crocus sativus ). Also, the extremely rare Tasmanian shrub Lomatia tasmanica is a triploid sterile species. There are few naturally occurring polyploid conifers . One example
5757-575: The allotetraploid yeast S. pastorianus show unequal contribution to the transcriptome . Phenotypic diversification is also observed following polyploidization and/or hybridization in fungi, producing the fuel for natural selection and subsequent adaptation and speciation. Other eukaryotic taxa have experienced one or more polyploidization events during their evolutionary history (see Albertin and Marullo, 2012 for review). The oomycetes , which are non-true fungi members, contain several examples of paleopolyploid and polyploid species, such as within
5858-621: The banana family, Musaceae . Banana plantations are subject to damage by parasitic nematodes and insect pests, and to fungal and bacterial diseases, one of the most serious being Panama disease which is caused by a Fusarium fungus. This and black sigatoka threaten the production of Cavendish bananas , the main kind eaten in the Western world, which is a triploid Musa acuminata . Plant breeders are seeking new varieties, but these are difficult to breed given that commercial varieties are seedless. To enable future breeding, banana germplasm
5959-458: The banana, causing the banana to soften as it ripens. The vivid yellow color many consumers in temperate climates associate with bananas is caused by ripening around 18 °C (64 °F), and does not occur in Cavendish bananas ripened in tropical temperatures (over 27 °C (81 °F)), which leaves them green. Bananas are transported over long distances from the tropics to world markets. To obtain maximum shelf life, harvest comes before
6060-414: The base, so that the plant as a whole is perennial . The inflorescence contains many petal-like bracts between rows of flowers. The female flowers (which can develop into fruit) appear in rows further up the stem (closer to the leaves) from the rows of male flowers. The ovary is inferior , meaning that the tiny petals and other flower parts appear at the tip of the ovary. The banana fruits develop from
6161-567: The basis for a range of studies in what might be called evolutionary cytology. Homoeologous chromosomes are those brought together following inter-species hybridization and allopolyploidization , and whose relationship was completely homologous in an ancestral species. For example, durum wheat is the result of the inter-species hybridization of two diploid grass species Triticum urartu and Aegilops speltoides . Both diploid ancestors had two sets of 7 chromosomes, which were similar in terms of size and genes contained on them. Durum wheat contains
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#17328549569796262-432: The best known is colchicine , which can result in chromosome doubling, though its use may have other less obvious consequences as well. Oryzalin will also double the existing chromosome content. Among mammals , a high frequency of polyploid cells is found in organs such as the brain, liver, heart, and bone marrow. It also occurs in the somatic cells of other animals , such as goldfish , salmon , and salamanders . It
6363-455: The botanical characteristics of Musa balbisiana , those primarily exhibiting the botanical characteristics of Musa acuminata , and those with characteristics of both. Researchers Norman Simmonds and Ken Shepherd proposed a genome-based nomenclature system in 1955. This system eliminated almost all the difficulties and inconsistencies of the earlier classification of bananas based on assigning scientific names to cultivated varieties. Despite this,
6464-457: The common name of bread wheat. Many agriculturally important plants of the genus Brassica are also tetraploids. Sugarcane can have ploidy levels higher than octaploid . Polyploidization can be a mechanism of sympatric speciation because polyploids are usually unable to interbreed with their diploid ancestors. An example is the plant Erythranthe peregrina . Sequencing confirmed that this species originated from E. × robertsii ,
6565-684: The common yellow dessert variety can be split lengthwise into three sections that correspond to the inner portions of the three carpels by manually deforming the unopened fruit. In cultivated varieties, fertile seeds are usually absent. A 2011 phylogenomic analysis using nuclear genes indicates the phylogeny of some representatives of the Musaceae family. Major edible kinds of banana are shown in boldface . Musa acuminata ssp. burmannica , Banana , S. India to Cambodia Musa ornata , Flowering banana of Southeast Asia Musa acuminata ssp. zebrina , Blood banana of Sumatra Musa mannii ,
6666-410: The destination country. These rooms are air-tight and filled with ethylene gas to induce ripening. This mimics the normal production of this gas as a ripening hormone. Ethylene stimulates the formation of amylase , an enzyme that breaks down starch into sugar, influencing the taste. Ethylene signals the production of pectinase , a different enzyme which breaks down the pectin between the cells of
6767-735: The development of refrigeration that allowed more time between harvesting and ripening. North American shippers like Lorenzo Dow Baker and Andrew Preston , the founders of the Boston Fruit Company started this process in the 1870s, with the participation of railroad builders like Minor C. Keith . Development led to the multi-national giant corporations like Chiquita and Dole . These companies were monopolistic , vertically integrated (controlling growing, processing, shipping and marketing) and usually used political manipulation to build enclave economies (internally self-sufficient, virtually tax exempt, and export-oriented, contributing little to
6868-407: The diploid species. A similar relationship exists between three diploid species of Tragopogon ( T. dubius , T. pratensis , and T. porrifolius ) and two allotetraploid species ( T. mirus and T. miscellus ). Complex patterns of allopolyploid evolution have also been observed in animals, as in the frog genus Xenopus . Organisms in which a particular chromosome, or chromosome segment,
6969-496: The early to middle of the Holocene the process was complete. From New Guinea, cultivated bananas spread westward into Island Southeast Asia . They hybridized with other (possibly independently domesticated) subspecies of Musa acuminata as well as M. balbisiana in the Philippines, northern New Guinea, and possibly Halmahera . These hybridization events produced the triploid cultivars of bananas commonly grown today. The banana
7070-581: The ends of a spectrum of divergence between parental subgenomes. Polyploids that fall between these two extremes, which are often referred to as segmental allopolyploids, may display intermediate levels of polysomic inheritance that vary by locus. About half of all polyploids are thought to be the result of autopolyploidy, although many factors make this proportion hard to estimate. Allopolyploids or amphipolyploids or heteropolyploids are polyploids with chromosomes derived from two or more diverged taxa. As in autopolyploidy, this primarily occurs through
7171-410: The entire population. Kindia has a tropical savanna climate ( Köppen climate classification Aw ). Banana A banana is an elongated, edible fruit – botanically a berry – produced by several kinds of large treelike herbaceous flowering plants in the genus Musa . In some countries, cooking bananas are called plantains, distinguishing them from dessert bananas . The fruit
7272-586: The estates at Episkopi, near modern-day Limassol , including the region's banana plantations. In the early modern period , bananas were encountered by European explorers during the Magellan expedition in 1521, in both Guam and the Philippines . Lacking a name for the fruit, the ship's historian Antonio Pigafetta described them as "figs more than one palm long." Bananas were introduced to South America by Portuguese sailors who brought them from West Africa in
7373-471: The evolved polyploids. The high degree of homology among duplicated chromosomes causes autopolyploids to display polysomic inheritance . This trait is often used as a diagnostic criterion to distinguish autopolyploids from allopolyploids, which commonly display disomic inheritance after they progress past the neopolyploid stage. While most polyploid species are unambiguously characterized as either autopolyploid or allopolyploid, these categories represent
7474-592: The export market, such as Colombia, Costa Rica, Ecuador, and Guatemala; worldwide they cover only 8–10% of production. Mutation breeding can be used in this crop. Aneuploidy is a source of significant variation in allotriploid varieties. For one example, it can be a source of TR4 resistance . Lab protocols have been devised to screen for such aberrations and for possible resulting disease resistances. Wild Musa spp. provide useful resistance genetics, and are vital to breeding for TR4 resistance, as shown in introgressed resistance from wild relatives. Bananas form
7575-489: The fact that "seedless" varieties do rarely produce seeds; they obtained around fifteen seeds from some 30,000 cultivated plants, pollinated by hand with pollen from wild Asian bananas. As of 2018 , bananas are exported in larger volume and to a larger value than any other fruit. In 2022, world production of bananas and plantains combined was 179 million tonnes, led by India and China with a combined total of 26% of global production. Other major producers were Uganda, Indonesia,
7676-474: The family Musaceae . The APG III system assigns Musaceae to the order Zingiberales , part of the commelinid clade of the monocotyledonous flowering plants. Some 70 species of Musa were recognized by the World Checklist of Selected Plant Families as of January 2013 ; several produce edible fruit, while others are cultivated as ornamentals. The classification of cultivated bananas has long been
7777-604: The four expected if it were truly a tetraploid. This rodent is not a rat , but kin to guinea pigs and chinchillas . Its "new" diploid (2 n ) number is 102 and so its cells are roughly twice normal size. Its closest living relation is Octomys mimax , the Andean Viscacha-Rat of the same family, whose 2 n = 56. It was therefore surmised that an Octomys -like ancestor produced tetraploid (i.e., 2 n = 4 x = 112) offspring that were, by virtue of their doubled chromosomes, reproductively isolated from their parents. Polyploidy
7878-436: The frog, Xenopus (an extension of the work of Briggs and King in 1952) that were able to develop to the tadpole stage. The British scientist J. B. S. Haldane hailed the work for its potential medical applications and, in describing the results, became one of the first to use the word " clone " in reference to animals. Later work by Shinya Yamanaka showed how mature cells can be reprogrammed to become pluripotent, extending
7979-414: The fruit is mature. The fruit requires careful handling, rapid transport to ports, cooling, and refrigerated shipping. The goal is to prevent the bananas from producing their natural ripening agent, ethylene. This technology allows storage and transport for 3–4 weeks at 13 °C (55 °F). On arrival, bananas are held at about 17 °C (63 °F) and treated with a low concentration of ethylene. After
8080-425: The fusion of unreduced (2 n ) gametes, which can take place before or after hybridization . In the former case, unreduced gametes from each diploid taxon – or reduced gametes from two autotetraploid taxa – combine to form allopolyploid offspring. In the latter case, one or more diploid F 1 hybrids produce unreduced gametes that fuse to form allopolyploid progeny. Hybridization followed by genome duplication may be
8181-509: The fusion of unreduced (2 n ) gametes, which results in either triploid ( n + 2 n = 3 n ) or tetraploid (2 n + 2 n = 4 n ) offspring. Triploid offspring are typically sterile (as in the phenomenon of triploid block ), but in some cases they may produce high proportions of unreduced gametes and thus aid the formation of tetraploids. This pathway to tetraploidy is referred to as the triploid bridge . Triploids may also persist through asexual reproduction . In fact, stable autotriploidy in plants
8282-648: The genus Phytophthora . Some species of brown algae ( Fucales , Laminariales and diatoms ) contain apparent polyploid genomes. In the Alveolata group, the remarkable species Paramecium tetraurelia underwent three successive rounds of whole-genome duplication and established itself as a major model for paleopolyploid studies. Each Deinococcus radiodurans bacterium contains 4-8 copies of its chromosome . Exposure of D. radiodurans to X-ray irradiation or desiccation can shatter its genomes into hundred of short random fragments. Nevertheless, D. radiodurans
8383-849: The host economy). Their political maneuvers, which gave rise to the term banana republic for states such as Honduras and Guatemala, included working with local elites and their rivalries to influence politics or playing the international interests of the United States, especially during the Cold War , to keep the political climate favorable to their interests. The vast majority of the world's bananas are cultivated for family consumption or for sale on local markets. They are grown in large quantities in India, while many other Asian and African countries host numerous small-scale banana growers who sell at least some of their crop. Peasants with smallholdings of 1 to 2 acres in
8484-429: The large bacterium Epulopiscium fishelsoni . Hence ploidy is defined with respect to a cell. A monoploid has only one set of chromosomes and the term is usually only applied to cells or organisms that are normally diploid. The more general term for such organisms is haploid . A polyploid that is newly formed. That has become polyploid in more recent history; it is not as new as a neopolyploid and not as old as
8585-461: The late 6th century AD. Malagasy people colonized Madagascar from South East Asia around 600 AD onwards. Glucanase and two other proteins specific to bananas were found in dental calculus from the early Iron Age (12th century BCE) Philistines in Tel Erani in the southern Levant . Another wave of introductions later spread bananas to other parts of tropical Asia, particularly Indochina and
8686-518: The males' DNA into the offspring. While some tissues of mammals, such as parenchymal liver cells, are polyploid, rare instances of polyploid mammals are known, but most often result in prenatal death. An octodontid rodent of Argentina 's harsh desert regions, known as the plains viscacha rat ( Tympanoctomys barrerae ) has been reported as an exception to this 'rule'. However, careful analysis using chromosome paints shows that there are only two copies of each chromosome in T. barrerae , not
8787-567: The name was borrowed into the Austronesian languages and across Asia, accompanying the cultivation of the banana as it was brought to new areas, via the Dravidian languages of India, into Arabic as a Wanderwort . The word "banana" is thought to be of West African origin, possibly from the Wolof word banaana , and passed into English via Spanish or Portuguese . Musa is the type genus in
8888-408: The number of chromosome sets in the nucleus . The letter x is used to represent the number of chromosomes in a single set: Autopolyploids are polyploids with multiple chromosome sets derived from a single taxon . Two examples of natural autopolyploids are the piggyback plant, Tolmiea menzisii and the white sturgeon, Acipenser transmontanum . Most instances of autopolyploidy result from
8989-437: The original names are still recognized by some authorities, leading to confusion. The accepted scientific names for most groups of cultivated bananas are Musa acuminata Colla and Musa balbisiana Colla for the ancestral species, and Musa × paradisiaca L. for the hybrid of the two. An unusual feature of the genetics of the banana is that chloroplast DNA is inherited maternally, while mitochondrial DNA
9090-417: The parents, but the initial hybrids are sterile. After polyploidization, the hybrid becomes fertile and can thus be further propagated to become triticale. In some situations, polyploid crops are preferred because they are sterile. For example, many seedless fruit varieties are seedless as a result of polyploidy. Such crops are propagated using asexual techniques, such as grafting . Polyploidy in crop plants
9191-411: The peel. The fruit has been described as a "leathery berry". There is a protective outer layer (a peel or skin) with numerous long, thin strings ( Vascular bundles ), which run lengthwise between the skin and the edible inner white flesh. The peel is less palatable and usually discarded after peeling the fruit, optimally done from the blossom end, but often started from the stalk end. The inner part of
9292-715: The possibilities to non-stem cells. Gurdon and Yamanaka were jointly awarded the Nobel Prize in 2012 for this work. True polyploidy rarely occurs in humans, although polyploid cells occur in highly differentiated tissue, such as liver parenchyma , heart muscle, placenta and in bone marrow. Aneuploidy is more common. Polyploidy occurs in humans in the form of triploidy , with 69 chromosomes (sometimes called 69, XXX), and tetraploidy with 92 chromosomes (sometimes called 92, XXXX). Triploidy, usually due to polyspermy , occurs in about 2–3% of all human pregnancies and ~15% of miscarriages. The vast majority of triploid conceptions end as
9393-545: The prevalence of allopolyploidy among crop species. Both bread wheat and triticale are examples of an allopolyploids with six chromosome sets. Cotton , peanut , and quinoa are allotetraploids with multiple origins. In Brassicaceous crops, the Triangle of U describes the relationships between the three common diploid Brassicas ( B. oleracea , B. rapa , and B. nigra ) and three allotetraploids ( B. napus , B. juncea , and B. carinata ) derived from hybridization among
9494-796: The processes of speciation and eco-niche exploitation. The mechanisms leading to novel variation in newly formed allopolyploids may include gene dosage effects (resulting from more numerous copies of genome content), the reunion of divergent gene regulatory hierarchies, chromosomal rearrangements, and epigenetic remodeling, all of which affect gene content and/or expression levels. Many of these rapid changes may contribute to reproductive isolation and speciation. However, seed generated from interploidy crosses , such as between polyploids and their parent species, usually have aberrant endosperm development which impairs their viability, thus contributing to polyploid speciation . Polyploids may also interbreed with diploids and produce polyploid seeds, as observed in
9595-460: The production of aneuploid gametes. Natural or artificial selection for fertility can quickly stabilize meiosis in autopolyploids by restoring bivalent pairing during meiosis. Rapid adaptive evolution of the meiotic machinery, resulting in reduced levels of multivalents (and therefore stable autopolyploid meiosis) has been documented in Arabidopsis arenosa and Arabidopsis lyrata , with specific adaptive alleles of these species shared between only
9696-419: The production of polyploid cells. This process can be useful in plant breeding, especially when attempting to introgress germplasm across ploidal levels. Autopolyploids possess at least three homologous chromosome sets, which can lead to high rates of multivalent pairing during meiosis (particularly in recently formed autopolyploids, also known as neopolyploids) and an associated decrease in fertility due to
9797-743: The region between Java , Borneo , and New Guinea ; while Pacific plantains were introduced to the Pacific Islands from either eastern New Guinea or the Bismarck Archipelago . 21st century discoveries of phytoliths in Cameroon dating to the first millennium BCE triggered a debate about the date of first cultivation in Africa. There is linguistic evidence that bananas were known in East Africa or Madagascar around that time. The earliest prior evidence indicates that cultivation dates to no earlier than
9898-642: The same number of chromosomes, and the chromosomes are joined in pairs of homologous chromosomes. However, some organisms are polyploid . Polyploidy is especially common in plants. Most eukaryotes have diploid somatic cells , but produce haploid gametes (eggs and sperm) by meiosis . A monoploid has only one set of chromosomes, and the term is usually only applied to cells or organisms that are normally diploid. Males of bees and other Hymenoptera , for example, are monoploid. Unlike animals, plants and multicellular algae have life cycles with two alternating multicellular generations . The gametophyte generation
9999-519: Was from naturally occurring parthenocarpic (seedless) individuals of Musa banksii in New Guinea . These were cultivated by Papuans before the arrival of Austronesian-speakers . Numerous phytoliths of bananas have been recovered from the Kuk Swamp archaeological site and dated to around 10,000 to 6,500 BP . Foraging humans in this area began domestication in the late Pleistocene using transplantation and early cultivation methods. > By
10100-412: Was induced in fish by Har Swarup (1956) using a cold-shock treatment of the eggs close to the time of fertilization, which produced triploid embryos that successfully matured. Cold or heat shock has also been shown to result in unreduced amphibian gametes, though this occurs more commonly in eggs than in sperm. John Gurdon (1958) transplanted intact nuclei from somatic cells to produce diploid eggs in
10201-674: Was one of the key crops that enabled farming to begin in Papua New Guinea. From Island Southeast Asia, bananas became part of the staple domesticated crops of Austronesian peoples . These ancient introductions resulted in the banana subgroup now known as the true plantains , which include the East African Highland bananas and the Pacific plantains (the Iholena and Maoli-Popo'ulu subgroups). East African Highland bananas originated from banana populations introduced to Madagascar probably from
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