Đa dạng di truyền là tổng số các đặc điểm di truyền trong thành phần di truyền của một loài. Nó khác với biến dị di truyền, thuật ngữ dùng để mô tả xu hướng biến đổi của các đặc điểm di truyền. Đa dạng di truyền là một cách để các quần thể có thể thích nghi được với môi trường sống thay đổi. Với nhiều biến đổi hơn, một số cá thể trong một quần thể sẽ có cơ hội cao hơn trong việc sở hữu những biến dị alen phù hợp với môi trường.
GENETIC DIVERSITY Ngon T.TRUONG Molecular Biology Laboratory Content: Introduction Mechanism of Genetic Diversity (GD) Where is GD ? Methods & Indexes for identifying GD Genetic diversity-measures Risks causing Genetic erosion Methods for enhancing & maitaining GD BioPro : tool for analyzing genetic diversity Conclusion Introduction: Biodiversity World wildlife fund (1998) defines : - all living organism on the planet - genes they contain - ecosystems they reside in Definition Species Biodiversity Genetic Ecology Genetic Diversity GD refers to the variation at the level of individual genes (polymorphism), and provides a mechanism for population to adapt to their ever-changing environment The more variation, the better the chance that at least some of the individuals will have an allelic variant being suited for the new environment Fig Genetic Diversity in human being Fig Genetic Diversity in mungbean seeds (Vigna sp.) Fig Genetic Diversity in hot pepper fruits (Capsicum sp.) Why? Genes Chromosomes Adaptation Changed Evolution Centers of origin Where? Diversity How importance? How? Mechanism Mechanism of Genetic Diversity Jumping Gene : Barbara Mc Clintock, 1951 (video.) Recombination : meiosis Variations : gene mutation : deletion, insertion (animation) chromosomes variation: - in number : euploidy, aneuploidy - in morphological : translocation, inversion Crossing over (Meiosis) Duplication Deletion Inversion Reciprocal Translocation Ring Chromosome Effects of genetic variation Vavilov, 1951 1/ Benefits : - Medicine : providing medicinal plants - Agriculture : enhancing soil fertility, controlling epidemy, providing food safety - Environment : limiting pollution 2/ Importance : varieties, species adapted for ecological conditions valuable genes as parental material source to make cross Methods for identifying GD P= G+E PHENOTYPE GENOTYPE Traits: Qualitative Quantitative ENVIRONMENT DNA Genetic Diversity – measures Source: Lee’s course basic methods to determine which alleles are present at a given locus All techniques use electrophoresis Protein electrophoresis – indirect, but commonly done Restriction Fragment Length Polymorphism (RFLP) Random Amplification of Polymorphic DNA (RAPD’s) Simple Sequence Repeat (SSR) polymorphisms DNA sequencing (fingerprinting) Polymorphic bands by RAPD marker Source: Ngon & Nelson 2001 M1 10 15 21 Polymorphic band by SSR marker Source : Ngon & Nelson 2001 M 10 15 20 M ABI systems Diversity indices Shannon Simpson McIntosh Brillouin Gleason Margalet Menhinick Standard deviation (SD) Keywords & formulas Richness : number of species/1 area unit Abundance : number of individual in certain species Shannon H p i ln p i Simpson D 1 S i 1 pi S i1 Similarity indices Simple Matching Coefficient Jaccard index Sorensen index Ochiai,Kendall, Morisita, Horn indexes Pearson correlation index Similarity percentage : Whittaker Similarity index : Bray Curtis Genetic distance: Euclide, D2 Mahalanobis Risks causing Genetic erosion : Putting genetic resource in unapproriate ecological conditions, and living environment; Changing in cropping system; Destroying living environment; Market pressure; Natural calamity, or catastrophe by human; Setting up unapproriate agricultural policy Methods for enhancing genetic diversity: genetic resource : introduce, making cross, mutation, wild species, transgenics cropping system: rotation, intercrop, overlapping crop ecological systems : crops + fish feeding crops + shrimp feeding crops + living organism feeding in flooding regions BioPro software : tool for analyzing biodiversity Analyse descriptor parameters : mean, variance, SD etc Analyze biodiversity indexes : Shannon, Simpson, etc Analyse genetic diversity, species diversity Cluster analysis (CA) Principal Component Analysis (PCA) Correspondence Analysis Can interface with other softwares EXCEL,ACCESS 10 Summaries: Why? Living Organisms Adaptation Evolution to occur? Genes : jumping; mutation Variation in chromosomes: number; morphology How to identify? Phenotype evaluation Genotype analysis: Protein, DNA markers to analyse? Softwares : common; professional (Biopro) Definition of genetic variations A gene mutation is a situation where a new allele arises through a change in the DNA code A chromosome variation is a situation where a segment of chromosome, a whole chromosome, or a set of chromosomes changes Transposable elements are DNA sequences which have the capacity to move about the genome References Heal, G et al Genetic Diversity and Interdependent Crop Choices in Agriculture In: Genetic diversity in Agriculture http://www.rewhc.org/biomeasures.shtml Brown, T., T Hodgkin 2003 Maintaining Plant Genetic Diversity in Agroecosystems IPGRI’s report Hawtin, G 2002 Biotechnolgy in the maintenance and use of Crop Genetic Diversity IPGRI Fedoroff, N 2001 How jumping genes were discovered http://structbio.nature.com NBII homepage Biodiversity-Genetic Diversity Sivaprakash, K.R et al 2004 Genetic diversity of black gram (Vigna mungo) landraces as evaluated by AFLP markers Current Science, vol.86 Baranek, M et al 2002 Evaluation of Genetic Diversity in 19 Glycine max (L.) Merr Accessions included in the Czech National Collection of Soybean Genotypes Czech J Genet Plant Breed 38: 69-74 Falco, S.D., and C Perrings 2003 Crop Genetic Diversity, Productivity and Stability of Agroecosystems A theoretical and Empirical investigation Scottish Journ of Political Economy Vol 50 N.2 10 Brown-Guerdira, G.L., J.A Thompson, R.L Nelson, and M.L Warburton 2000 Evaluation of Genetic Diversity of Soybean Introductions and North American Ancestor Using RAPD and SSR markers 11 THANK YOU VERY MUCH !! 12 ... shrimp feeding crops + living organism feeding in flooding regions BioPro software : tool for analyzing biodiversity Analyse descriptor parameters : mean, variance, SD etc Analyze biodiversity... Genetic Diversity IPGRI Fedoroff, N 2001 How jumping genes were discovered http://structbio.nature.com NBII homepage Biodiversity-Genetic Diversity Sivaprakash, K.R et al 2004 Genetic diversity... genetic variation Vavilov, 1951 1/ Benefits : - Medicine : providing medicinal plants - Agriculture : enhancing soil fertility, controlling epidemy, providing food safety - Environment : limiting pollution