Misplaced Pages

#124875

64-497: Clayton Oscar Person was the first scientist to study plant pathosystem ratios rather than genetics ratios in host-parasite systems. In doing so, he discovered the differential interaction that is common to all gene-for-gene relationships and that is now known as the Person differential interaction. There are several different classes of R genes. The major classes are the NBS-LRR genes and

128-625: A respiratory burst . The main products of the neutrophil respiratory burst are strong oxidizing agents including hydrogen peroxide , free oxygen radicals and hypochlorite . Neutrophils are the most abundant type of phagocyte, normally representing 50–60% of the total circulating leukocytes, and are usually the first cells to arrive at the site of an infection. The bone marrow of a normal healthy adult produces more than 100 billion neutrophils per day, and more than 10 times that many per day during acute inflammation. Dendritic cells (DCs) are phagocytic cells present in tissues that are in contact with

192-485: A broad term that indicates a gene that encodes any determinant of the specificity of the interaction with the host. Thus, this term can encompass some conserved microbial signatures, also called pathogen or microbe associated molecular patterns (PAMPs or MAMPs), and pathogen effectors (e.g. bacterial type III effectors and oomycete effectors) as well as any genes that control variation in the activity of those molecules. Intracellular recognition of an avirulence gene product

256-398: A cationic detergent. Many acute-phase proteins of inflammation are involved in the coagulation system. Increased levels of lactoferrin and transferrin inhibit bacterial growth by binding iron, an essential bacterial nutrient. The innate immune response to infectious and sterile injury is modulated by neural circuits that control cytokine production period. The inflammatory reflex

320-419: A central role in antiviral host defense and a cell's antiviral state. Viral components are recognized by different receptors: Toll-like receptors are located in the endosomal membrane and recognize double-stranded RNA (dsRNA), MDA5 and RIG-I receptors are located in the cytoplasm and recognize long dsRNA and phosphate-containing dsRNA respectively. When the cytoplasmic receptors MDA5 and RIG-I recognize

384-577: A class of its own. It encodes a Ser/Thr kinase but has no LRR. It requires the presence of a linked NBS-LRR gene, prf , for activity. R gene specificity (recognising certain Avr gene products) is believed to be conferred by the leucine rich repeats. LRRs are multiple, serial repeats of a motif of roughly 24 amino acids in length, with leucines or other hydrophobic residues at regular intervals. Some may also contain regularly spaced prolines and arginines . LRRs are involved in protein-protein interactions, and

448-423: A condition known as "missing self". This term describes cells with abnormally low levels of a cell-surface marker called MHC I ( major histocompatibility complex ) - a situation that can arise in viral infections of host cells. They were named "natural killer" because of the initial notion that they do not require activation in order to kill cells that are "missing self". The MHC makeup on the surface of damaged cells

512-402: A major contribution to the development of a rigorous theoretical basis for our understanding of how the genetic structure of parasitic populations interacts with that of their host populations. This was known as the gene-for-gene relationship . His theoretical methods have been applied widely in the practical management of parasitic diseases in agriculture and forestry. After service overseas in

576-651: A member of the Canadian National Committee for the International Union of Biological Science. His scholarly achievements have received wide recognition. He has been an Invited participant in numerous international symposia. In 1971 he was a visiting professor at Punjab Agricultural University . In 1975 he served as consultant to the FAO (United Nations) on coffee diseases in Ethiopia . He was an invited scholar at

640-488: A modified form of the complement response known as the prophenoloxidase (proPO) system. Antimicrobial peptides are an evolutionarily conserved component of the innate immune response found among all classes of life and represent the main form of invertebrate systemic immunity . Several species of insect produce antimicrobial peptides known as defensins and cecropins . In invertebrates, PRRs trigger proteolytic cascades that degrade proteins and control many of

704-529: A part of a plant helps stop infection spread. Most plant immune responses involve systemic chemical signals sent throughout a plant. Plants use PRRs to recognize conserved microbial signatures. This recognition triggers an immune response. The first plant receptors of conserved microbial signatures were identified in rice ( XA21 , 1995) and in Arabidopsis ( FLS2 , 2000). Plants also carry immune receptors that recognize variable pathogen effectors. These include

SECTION 10

#1732890980125

768-492: A pathogen keeping a protein that only serves to have it recognised by the plant, it is believed that the products of Avr genes play an important role in virulence in genetically susceptible hosts. Example: AvrPto is a small triple-helix protein that, like several other effectors, is targeted to the plasma membrane by N-myristoylation. AvrPto is an inhibitor of PRR kinase domains. PRRs signal plants to induce immunity when PAMPs are detected. The ability to target receptor kinases

832-547: A plasma-clotting protein. On the other hand, in the horseshoe crab clotting system, components of proteolytic cascades are stored as inactive forms in granules of hemocytes, which are released when foreign molecules, like lipopolysaccharides enter. Members of every class of pathogen that infect humans also infect plants. Although the exact pathogenic species vary with the infected species, bacteria, fungi, viruses, nematodes, and insects can all cause plant disease . As with animals, plants attacked by insects or other pathogens use

896-460: A requirement of caspase -1-like proteolytic activity of VPEγ , a cysteine protease that regulates cell disassembly during cell death. "Resistance" (R) proteins, encoded by R genes , are widely present in plants and detect pathogens. These proteins contain domains similar to the NOD Like Receptors and TLRs. Systemic acquired resistance (SAR) is a type of defensive response that renders

960-519: A set of complex metabolic responses that lead to the formation of defensive chemical compounds that fight infection or make the plant less attractive to insects and other herbivores . (see: plant defense against herbivory ). Like invertebrates, plants neither generate antibody or T-cell responses nor possess mobile cells that detect and attack pathogens. In addition, in case of infection, parts of some plants are treated as disposable and replaceable, in ways that few animals can. Walling off or discarding

1024-402: A substantial portion of the mammalian gastrointestinal flora . Species such as B. fragilis are opportunistic pathogens , causing infections of the peritoneal cavity . They inhibit phagocytosis by affecting the phagocytes receptors used to engulf bacteria. They may also mimic host cells so the immune system does not recognize them as foreign. Staphylococcus aureus inhibits the ability of

1088-583: A virus the conformation between the caspase-recruitment domain (CARD) and the CARD-containing adaptor MAVS changes. In parallel, when TLRs in the endocytic compartments recognize a virus the activation of the adaptor protein TRIF is induced. Both pathways converge in the recruitment and activation of the IKKε/TBK-1 complex, inducing dimerization of transcription factors IRF3 and IRF7 , which are translocated in

1152-398: Is a prototypical neural circuit that controls cytokine production in the spleen . Action potentials transmitted via the vagus nerve to the spleen mediate the release of acetylcholine , the neurotransmitter that inhibits cytokine release by interacting with alpha7 nicotinic acetylcholine receptors ( CHRNA7 ) expressed on cytokine-producing cells. The motor arc of the inflammatory reflex

1216-616: Is altered and the NK cells become activated by recognizing this. Normal body cells are not recognized and attacked by NK cells because they express intact self MHC antigens. Those MHC antigens are recognized by killer cell immunoglobulin receptors (KIR) that slow the reaction of NK cells. The NK-92 cell line does not express KIR and is developed for tumor therapy. Like other 'unconventional' T cell subsets bearing invariant T cell receptors (TCRs), such as CD1d -restricted Natural Killer T cells , γδ T cells exhibit characteristics that place them at

1280-470: Is an important part of the healing process following tissue injury. Macrophages, from the Greek, meaning "large eaters", are large phagocytic leukocytes, which are able to move beyond the vascular system by migrating through the walls of capillary vessels and entering the areas between cells in pursuit of invading pathogens. In tissues, organ-specific macrophages are differentiated from phagocytic cells present in

1344-467: Is enveloped (i.e., the particle is now inside the cell). Once inside the cell, the invading pathogen is contained inside a phagosome , which merges with a lysosome . The lysosome contains enzymes and acids that kill and digest the particle or organism. In general, phagocytes patrol the body searching for pathogens, but are also able to react to a group of highly specialized molecular signals produced by other cells, called cytokines . The phagocytic cells of

SECTION 20

#1732890980125

1408-504: Is hyperphosphorylated by the Avr proteins. Another high profile study that supports the guard hypothesis shows that the RPS5 pair uses PBS1, a protein kinase as a guardee against AvrPphB. Yeast two-hybrid studies of the tomato Pto/Prf/AvrPto interaction showed that the Avirulence protein, AvrPto, interacted directly with Pto despite Pto not having an LRR. This makes Pto the guardee protein, which

1472-675: Is protected by the NBS-LRR protein Prf. However, Pto is a resistance gene alone, which is an argument against the guard hypothesis. Clayton Oscar Person Clayton Oscar Person , CM FRSC (May 16, 1922 – September 1, 1990) was recognized internationally as an authority on the genetics of host-parasite relations. He was born and raised in Aylesbury, Saskatchewan , Canada and died in Vancouver, British Columbia , Canada. His writings have made

1536-493: Is required for the virulence function of AvrPto in plants. However, Pto is a resistant gene that can detect AvrPto and induce immunity as well. AvrPto is an ancient effector that is conserved in many P. syringae strains, whereas Pto R gene is only found in a few wild tomato species. This suggests recent evolution of the Pto R gene and the pressure to evolve to target AvrPto, turning a virulence effector to an avirulence effector. Unlike

1600-606: Is termed the cholinergic anti-inflammatory pathway . The parts of the innate immune system display specificity for different pathogens. Innate immune system cells prevent free growth of microorganisms within the body, but many pathogens have evolved mechanisms to evade it. One strategy is intracellular replication, as practised by Mycobacterium tuberculosis , or wearing a protective capsule, which prevents lysis by complement and by phagocytes, as in Salmonella . Bacteroides species are normally mutualistic bacteria, making up

1664-470: Is there direct interaction between the R gene product and the Avr gene product. For example, both FLS2 and XA21 interact with the microbial peptides. In contrast, for the NBS-LRR class of R genes, direct interaction has not been shown for most of the R/avr pairs. This lack of evidence for a direct interaction led to the formation of the guard hypothesis for the NBS-LRR class of R genes. This model proposes that

1728-507: The 2′,5′-oligoadenylate synthetase family, which degrades viral RNA. Some viruses evade this by producing molecules that interfere with IFN production. For example, the Influenza A virus produces NS1 protein, which can bind to host and viral RNA, interact with immune signaling proteins or block their activation by ubiquitination , thus inhibiting type I IFN production. Influenza A also blocks protein kinase R activation and establishment of

1792-892: The Royal Canadian Navy from 1941-1945, he returned to enroll at the University of Saskatchewan where he was awarded Honours in Biology in 1950 and the MA in 1951. He studied for the Ph.D. at the University of Alberta , then spent two post-doctoral years abroad — one at the University of Lund , Sweden and another at the John Innes Institute in England. Dr. Person was employed for several years (1956-1961) as Research Officer with Agriculture Canada in its Dominion Rust Research Laboratory , Winnipeg. He

1856-415: The blood vessels , and attract phagocytes, especially neutrophils. Neutrophils then trigger other parts of the immune system by releasing factors that summon additional leukocytes and lymphocytes. Cytokines produced by macrophages and other cells of the innate immune system mediate the inflammatory response. These cytokines include TNF , HMGB1 , and IL-1 . The inflammatory response is characterized by

1920-576: The plant cell cytoplasm . The PRR class of R genes includes the rice XA21 resistance gene that recognizes the ax21 peptide and the Arabidopsis FLS2 peptide that recognizes the flg22 peptide from flagellin. There are other classes of R genes, such as the extracellular LRR class of R genes; examples include rice Xa21D for resistance against Xanthomonas and the cf genes of tomato that confer resistance against Cladosporium fulvum . The Pseudomonas tomato resistance gene (Pto) belongs to

1984-642: The Canadian Botanical Association awarded him the George Lawson Medal. Innate immunity#Host defense in plants The innate immune system or nonspecific immune system is one of the two main immunity strategies in vertebrates (the other being the adaptive immune system ). The innate immune system is an alternate defense strategy and is the dominant immune system response found in plants , fungi , prokaryotes , and invertebrates (see Beyond vertebrates ). The major functions of

Gene-for-gene relationship - Misplaced Pages Continue

2048-584: The MAMP or PAMP class of avr genes that are recognized by the host PRRs, the targets of bacterial effector avr proteins appear to be proteins involved in plant innate immunity signaling, as homologues of Avr genes in animal pathogens have been shown to do this. For example, the AvrBs3 family of proteins possess DNA binding domains, nuclear localisation signals and acidic activation domains and are believed to function by altering host cell transcription. In only some cases

2112-411: The NBS-LRR class of proteins. When a part of a plant becomes infected with a microbial or viral pathogen, in case of an incompatible interaction triggered by specific elicitors , the plant produces a localized hypersensitive response (HR), in which cells at the site of infection undergo rapid apoptosis to prevent spread to other parts of the plant. HR has some similarities to animal pyroptosis , such as

2176-458: The R proteins interact, or guard, a protein known as the guardee which is the target of the Avr protein. When it detects interference with the guardee protein, it activates resistance. Several experiments support this hypothesis, e.g. the Rpm1 gene in Arabidopsis thaliana is able to respond to two completely unrelated avirulence factors from Pseudomonas syringae . The guardee protein is RIN4, which

2240-544: The Rockefeller Study and Conference Centre in Italy in 1982. Dr. Person is an acknowledged authority on the genetics of plant parasites. His major research contribution has been to clarify the genetic basis of microevolutionary change in host-parasite systems. His work constitutes a major contribution to modern theory of host-parasite interaction in plant populations. It has found important applications in plant breeding throughout

2304-473: The antiviral state. The dengue virus also inhibits type I IFN production by blocking IRF-3 phosophorylation using NS2B3 protease complex. Bacteria (and perhaps other prokaryotic organisms), utilize a unique defense mechanism, called the restriction modification system to protect themselves from pathogens, such as bacteriophages . In this system, bacteria produce enzymes , called restriction endonucleases , that attack and destroy specific regions of

2368-408: The blood called monocytes . Macrophages are the most efficient phagocytes and can phagocytose substantial numbers of bacteria or other cells or microbes. The binding of bacterial molecules to receptors on the surface of a macrophage triggers it to engulf and destroy the bacteria through the generation of a " respiratory burst ", causing the release of reactive oxygen species . Pathogens also stimulate

2432-645: The border between innate and adaptive immunity. γδ T cells may be considered a component of adaptive immunity in that they rearrange TCR genes to produce junctional diversity and develop a memory phenotype . The various subsets may be considered part of the innate immune system where a restricted TCR or NK receptors may be used as a pattern recognition receptor . For example, according to this paradigm, large numbers of Vγ9/Vδ2 T cells respond within hours to common molecules produced by microbes, and highly restricted intraepithelial Vδ1 T cells will respond to stressed epithelial cells. The coagulation system overlaps with

2496-434: The cascades. In the hemolymph, which makes up the fluid in the circulatory system of arthropods , a gel-like fluid surrounds pathogen invaders, similar to the way blood does in other animals. Various proteins and mechanisms are involved in invertebrate clotting. In crustaceans, transglutaminase from blood cells and mobile plasma proteins make up the clotting system, where the transglutaminase polymerizes 210 kDa subunits of

2560-492: The cell surface pattern recognition receptors (PRR). The protein products of the NBS-LRR R genes contain a nucleotide binding site (NBS) and a leucine rich repeat (LRR). The protein products of the PRRs contain extracellular, juxtamembrane, transmembrane and intracellular non-RD kinase domains. Within the NBS-LRR class of R genes are two subclasses: The protein products encoded by this class of resistance gene are located within

2624-516: The clinical signs of inflammation. PRR activation and its cellular consequences have been well-characterized as methods of inflammatory cell death, which include pyroptosis , necroptosis , and PANoptosis . These cell death pathways help clear infected or aberrant cells and release cellular contents and inflammatory mediators. Chemical factors produced during inflammation ( histamine , bradykinin , serotonin , leukotrienes , and prostaglandins ) sensitize pain receptors , cause local vasodilation of

Gene-for-gene relationship - Misplaced Pages Continue

2688-722: The complement cascade can be found in many non-mammalian species including plants , birds , fish , and some species of invertebrates . White blood cells (WBCs) are also known as leukocytes . Most leukocytes differ from other cells of the body in that they are not tightly associated with a particular organ or tissue; thus, their function is similar to that of independent, single-cell organisms. Most leukocytes are able to move freely and interact with and capture cellular debris, foreign particles, and invading microorganisms (although macrophages , mast cells , and dendritic cells are less mobile). Unlike many other cells, most innate immune leukocytes cannot divide or reproduce on their own, but are

2752-421: The entire plant resistant to a broad spectrum of infectious agents. SAR involves the production of chemical messengers , such as salicylic acid or jasmonic acid . Some of these travel through the plant and signal other cells to produce defensive compounds to protect uninfected parts, e.g., leaves. Salicylic acid itself, although indispensable for expression of SAR, is not the translocated signal responsible for

2816-418: The environment. Histamine dilates blood vessels , causing the characteristic signs of inflammation, and recruits neutrophils and macrophages. The word 'phagocyte' literally means 'eating cell'. These are immune cells that engulf, or ' phagocytose ', pathogens or particles. To engulf a particle or pathogen, a phagocyte extends portions of its plasma membrane , wrapping the membrane around the particle until it

2880-408: The external environment, mainly the skin (where they are often called Langerhans cells ), and the inner mucosal lining of the nose , lungs , stomach , and intestines . They are named for their resemblance to neuronal dendrites , but dendritic cells are not connected to the nervous system . Dendritic cells are very important in the process of antigen presentation , and serve as a link between

2944-563: The eyes and mouth. Inflammation is one of the first responses of the immune system to infection or irritation. Inflammation is stimulated by chemical factors released by injured cells. It establishes a physical barrier against the spread of infection and promotes healing of any damaged tissue following pathogen clearance. The process of acute inflammation is initiated by cells already present in all tissues, mainly resident macrophages , dendritic cells , histiocytes , Kupffer cells , and mast cells . These cells present receptors contained on

3008-544: The first vertebrates. Nevertheless, invertebrates possess mechanisms that appear to be precursors of these aspects of vertebrate immunity. Pattern recognition receptors (PRRs) are proteins used by nearly all organisms to identify molecules associated with microbial pathogens. TLRs are a major class of pattern recognition receptor, that exists in all coelomates (animals with a body-cavity), including humans. The complement system exists in most life forms. Some invertebrates, including various insects, crabs , and worms utilize

3072-447: The following symptoms: The complement system is a biochemical cascade of the immune system that helps, or "complements", the ability of antibodies to clear pathogens or mark them for destruction by other cells. The cascade is composed of many plasma proteins, synthesized in the liver , primarily by hepatocytes . The proteins work together to: The three different complement systems are classical, alternative and lectin. Elements of

3136-573: The greatest variation amongst resistance genes occurs in the LRR domain. LRR swapping experiments between resistance genes in flax rust resulted in the specificity of the resistance gene for the avirulence gene changing. Most resistance genes are autosomal dominant but there are some, most notably the mlo gene in barley , in which monogenic resistance is conferred by recessive alleles . mlo protects barley against nearly all pathovars of powdery mildew . The term "avirulence gene" remains useful as

3200-437: The immune system include macrophages, neutrophils , and dendritic cells. Phagocytosis of the hosts' own cells is common as part of regular tissue development and maintenance. When host cells die, either by apoptosis or by cell injury due to an infection, phagocytic cells are responsible for their removal from the affected site. By helping to remove dead cells preceding growth and development of new healthy cells, phagocytosis

3264-444: The immune system. Some products of the coagulation system can contribute to non-specific defenses via their ability to increase vascular permeability and act as chemotactic agents for phagocytic cells . In addition, some of the products of the coagulation system are directly antimicrobial . For example, beta-lysine , a protein produced by platelets during coagulation , can cause lysis of many Gram-positive bacteria by acting as

SECTION 50

#1732890980125

3328-597: The inability of the epidermis to retain moisture, and the presence of sebaceous glands in the dermis, produces an environment unsuitable for the survival of microbes . In the gastrointestinal and respiratory tract , movement due to peristalsis or cilia, respectively, helps remove infectious agents. Also, mucus traps infectious agents. Gut flora can prevent the colonization of pathogenic bacteria by secreting toxic substances or by competing with pathogenic bacteria for nutrients or cell surface attachment sites. The flushing action of tears and saliva helps prevent infection of

3392-813: The innate and adaptive immune systems . Basophils and eosinophils are cells related to the neutrophil. When activated by a pathogen encounter, histamine -releasing basophils are important in the defense against parasites and play a role in allergic reactions , such as asthma . Upon activation, eosinophils secrete a range of highly toxic proteins and free radicals that are highly effective in killing parasites, but may also damage tissue during an allergic reaction. Activation and release of toxins by eosinophils are, therefore, tightly regulated to prevent any inappropriate tissue destruction. Natural killer cells (NK cells) do not directly attack invading microbes. Rather, NK cells destroy compromised host cells, such as tumor cells or virus-infected cells, recognizing such cells by

3456-434: The innate immune system are to: Anatomical barriers include physical, chemical and biological barriers. The epithelial surfaces form a physical barrier that is impermeable to most infectious agents, acting as the first line of defense against invading organisms. Desquamation (shedding) of skin epithelium also helps remove bacteria and other infectious agents that have adhered to the epithelial surface. Lack of blood vessels,

3520-480: The macrophage to produce chemokines, which summon other cells to the site of infection. Neutrophils, along with eosinophils and basophils , are known as granulocytes due to the presence of granules in their cytoplasm, or as polymorphonuclear cells (PMNs) due to their distinctive lobed nuclei . Neutrophil granules contain a variety of toxic substances that kill or inhibit growth of bacteria and fungi. Similar to macrophages, neutrophils attack pathogens by activating

3584-429: The mechanisms of the innate immune system of invertebrates—including hemolymph coagulation and melanization . Proteolytic cascades are important components of the invertebrate immune system because they are turned on more rapidly than other innate immune reactions because they do not rely on gene changes. Proteolytic cascades function in both vertebrate and invertebrates, even though different proteins are used throughout

3648-483: The nucleus, where they induce IFN production with the presence of a particular transcription factor and activate transcription factor 2. IFN is secreted through secretory vesicles , where it can activate receptors on both the cell it was released from ( autocrine ) or nearby cells (paracrine). This induces hundreds of interferon-stimulated genes to be expressed. This leads to antiviral protein production, such as protein kinase R , which inhibits viral protein synthesis, or

3712-493: The phagocyte to respond to chemokine signals. M. tuberculosis , Streptococcus pyogenes , and Bacillus anthracis utilize mechanisms that directly kill the phagocyte. Bacteria and fungi may form complex biofilms , protecting them from immune cells and proteins; biofilms are present in the chronic Pseudomonas aeruginosa and Burkholderia cenocepacia infections characteristic of cystic fibrosis . Type I interferons (IFN), secreted mainly by dendritic cells , play

3776-815: The products of multipotent hematopoietic stem cells present in bone marrow . The innate leukocytes include: natural killer cells , mast cells, eosinophils , basophils ; and the phagocytic cells include macrophages , neutrophils , and dendritic cells, and function within the immune system by identifying and eliminating pathogens that might cause infection. Mast cells are a type of innate immune cell that resides in connective tissue and in mucous membranes. They are intimately associated with wound healing and defense against pathogens, but are also often associated with allergy and anaphylaxis . When activated, mast cells rapidly release characteristic granules, rich in histamine and heparin , along with various hormonal mediators and chemokines , or chemotactic cytokines into

3840-482: The surface or within the cell, named pattern recognition receptors (PRRs), which recognize molecules that are broadly shared by pathogens but distinguishable from host molecules, collectively referred to as pathogen-associated molecular patterns (PAMPs). At the onset of an infection, burn, or other injuries, these cells undergo activation (one of their PRRs recognizes a PAMP) and release inflammatory mediators , like cytokines and chemokines, which are responsible for

3904-417: The viral DNA of invading bacteriophages. Methylation of the host's own DNA marks it as "self" and prevents it from being attacked by endonucleases. Restriction endonucleases and the restriction modification system exist exclusively in prokaryotes. Invertebrates do not possess lymphocytes or an antibody-based humoral immune system, and it is likely that a multicomponent, adaptive immune system arose with

SECTION 60

#1732890980125

3968-830: The world. He was elected Fellow of the Royal Society of Canada in 1970, and was designated Fellow of the American Phytopathological Society in 1981. He was awarded the British Columbia Science Secretariat Medal in 1981, the Flavelle Medal by the Royal Society of Canada and the Medal of the Genetics Society of Canada, both in 1982. He was made a Member of the Order of Canada in 1986. In 1987

4032-431: Was first demonstrated by Gopalan et al 1996. They found that artificial expression of Pseudomonas syringae ' s avrB in the host Arabidopsis produced cell death when combined with expression of the host R gene , RPM1 . This proved recognition was occurring intracellularly and not on the surface. There is no common structure between avirulence gene products. Because there would be no evolutionary advantage to

4096-591: Was then appointed as the first Head of the Department of Genetics at the University of Alberta . In 1966 he joined the Department of Botany of the University of British Columbia . Dr. Person has served the Canadian scientific community in various capacities, including participation in the establishment of the Genetics Society of Canada and later as its president; as Chairman of the NSERC Committee for Plant Biology, and as

#124875