What is genetic diversity ? Training Workshop on Forest Biodiversity, Kuala Lumpur, Malaysia Thomas Geburek Department of Genetics Federal Research Centre for Forests, Natural Hazards, and Landscape (BFW) Austria

Conditions for Forest Ecosystem Stability Species diversity Temporal variation Spatial variation Patterns of interactions Training Workshop on Forest Biodiversity, Kuala Lumpur, Malaysia

Conditions for Forest Ecosystem Stability Species diversity Temporal variation Spatial variation Patterns of interactions Genetic diversity Training Workshop on Forest Biodiversity, Kuala Lumpur, Malaysia

material balance energy balance information balance Ecosystem identity can be regarded as the totality of Certain degree of constancy of the information needed; must be of a biological nature, and has its material basis in the hereditary substance DNA. Training Workshop on Forest Biodiversity, Kuala Lumpur, Malaysia

Noss (1990) Biodiversity – genetic, species, and landscape level

Significance of genetic diversity Adjustment to changing environmental conditions may be based on: physiological adaptation internal self-regulating mechanisms, the more (allelic) genes the better the physiological buffer epigenetic adaptation triggered by environmental signals, not based on Mendelian inheritance, may regulate gene expression over generations collective adaptation population adjusts its genetic composition through evolutionary factors Training Workshop on Forest Biodiversity, Kuala Lumpur, Malaysia

Forest trees are something special Longevity Spatial heterogeneity Training Workshop on Forest Biodiversity, Kuala Lumpur, Malaysia Pinus aristata Pinus sylvestris

Mother Nature has equipped tree species with a high amount of genetic diversity necessary to cope with environmental changes in evolutionary time scales. A long-term sustainable management of forest ecosystems requires the maintenance of genetic diversity in probably all tree populations. Training Workshop on Forest Biodiversity, Kuala Lumpur, Malaysia

Response functions of 10 Pinus sylvestris populations Rehfeldt et al. (2002) Training Workshop on Forest Biodiversity, Kuala Lumpur, Malaysia

They are resulted from: reduction in population size loss, deterioration or fragmentation of habitats accelerated climate change population and species fragmentation introduced pathogens hybridization with nonnative species, and other detrimental factors The fundamental problems of plant conservation genetics are loss of genetic diversity and harmful irreversible changes in population structure Most (if not all) of these are due to human activity (such as habitat alteration, pollution, overexploitation, etc). Training Workshop on Forest Biodiversity, Kuala Lumpur, Malaysia

The major objective of conservation genetics is to preserve the existing genetic diversity as potential for adaptation and evolution, and, therefore, to ensure that the adaptation and evolutionary potential of important regional tree species are maintained. “Wild species must have available a pool of genetic diversity if they are to survive environmental pressures ….. If this is not the case, extinction would appear inevitable.” (Otto Frankel 1983) Training Workshop on Forest Biodiversity, Kuala Lumpur, Malaysia

Key terms definition Genetic diversity (sensu lato) is the variety of alleles and genotypes present in a population, species or group of species. Genotype is the combination of alleles and genes in an organism. Phenotypic variation is the difference in morphology, physiology, or behavior among individuals of a species caused by genetic and environmental factors. Phenotype is the observed trait (physical, biochemical, behavioral, etc.) of an organism controlled by the interaction of its genes with the environment. Training Workshop on Forest Biodiversity, Kuala Lumpur, Malaysia

Genetic information is transmitted without chance to the next tree generation. Uniparental inheritance Training Workshop on Forest Biodiversity, Kuala Lumpur, Malaysia The vast majority of genetic information is maintained in the nucleus and is reshuffled from generation to generation. Biparental inheritance Where do we find genetic information ?

Individuals within a species may vary strongly phenotypically ! Training Workshop on Forest Biodiversity, Kuala Lumpur, Malaysia

Source: Brassica wildtype bushy dwarf wrinkly Training Workshop on Forest Biodiversity, Kuala Lumpur, Malaysia

Genetic Markers

Nuclear genome in trees DNA content varies significantly in angiosperms (1000-fold size variation) and gymnosperms (14- fold size variation). Number of genes presumably varies between und covering – centi- Morgan. Hypothetical explanation: different amount of junk DNA (higher content of repeated DNA or single-copy, non-transcribed DNA ). Training Workshop on Forest Biodiversity, Kuala Lumpur, Malaysia

Mitochondrial Genome Size varies between 200 kb and kb, most often between 300 kb and 600 kb. characteristic large, highly variable repeats Recombination between repeats may form a complex genome (in it simpliest form a master and a slaves genome genes (mainly for respiration) Training Workshop on Forest Biodiversity, Kuala Lumpur, Malaysia

Chloroplast Genome Size varies between 120 (gymnosperms) and 150 kb (angiosperms). Approx. 100 to 120 genes (mainly for photosynthesis) Genes are tightly packed, large non-coding regions are missing. Order of genes is nearly identical among all plant species. Mutation rate is two up to threefold lesser than in the nuclear DNA and up to four times larger than in mt-DNA. Training Workshop on Forest Biodiversity, Kuala Lumpur, Malaysia

Gene: What is it? 5’ utr 3’ utr DNA sequencer gel image Training Workshop on Forest Biodiversity, Kuala Lumpur, Malaysia

Levels of genetic organization Gene Text sequence ChromosomeChapter Genome Genepool Training Workshop on Forest Biodiversity, Kualar Lumpur, Malaysia 5-16 June 2006Training Workshop on Forest Biodiversity, Kuala Lumpur, Malaysia

Sum of environmental factors: variation of the site in time and space, light, water, nutrients, etc Phenotype Sum of genetic information: – genes (genotype) Training Workshop on Forest Biodiversity, Kuala Lumpur, Malaysia

How much genotype is in phenotype? Training Workshop on Forest Biodiversity, Kuala Lumpur, Malaysia

Organisms are different because of the genetic differences among individuals, different environments where individuals are growing, and interactions between genotypes and environments in which they exist. P = G + E + G×E Phenotype = Genotype + Environment + Interaction Training Workshop on Forest Biodiversity, Kuala Lumpur, Malaysia

How to separate between genetic and environmental effects? Common Garden Experiment Environment Gene Mixture of both Training Workshop on Forest Biodiversity, Kuala Lumpur, Malaysia

provided insights into the adaptive variation of complex traits often geographical patterns, such as steep latitudinal or altitudinal clines time consuming and relatively expensive; solely based on the phenotypes can estimate genetic parameters on measurable traits can neither provide information on what particular genes and how many of them are involved in adaptation nor how much of phenotypic variation can be explained by genetic variation in these genes Training Workshop on Forest Biodiversity, Kuala Lumpur, Malaysia Common garden experiments

Genetic diversity (1) Quantitative genetic variation (genetic variances) (2) Qualitative genetic diversity  information at single gene(s) must be available Training Workshop on Forest Biodiversity, Kuala Lumpur, Malaysia  additive variance ( = variances of the breeding values), non-additive genetic variance

Variation within genes alleles & haplotypes Variation within individuals individual heterozygosity Variation within populations allele frequencies, average heterozygosity, average number of polymorphic alleles and loci and other summary statistics, effective number of alleles, pairwise individual genetic similarity or distance, etc Variation among populations differentiation and genetic distance (pairwise and average) Training Workshop on Forest Biodiversity, Kuala Lumpur, Malaysia

How much genetic diversity is needed? Peterson et al. (1998) Darwin/MacArthur‘s Model Ehrlich & Ehrlich‘s „rivet“ Model Walker‘s „driver and passenger“ Model Lawton‘s idiosyncratic Model Training Workshop on Forest Biodiversity, Kuala Lumpur, Malaysia

Oostermeijer et al. (2005) Gentiana pneumonanthe How much genetic diversity is needed? The so-called Allee effect Training Workshop on Forest Biodiversity, Kuala Lumpur, Malaysia

By now you should know Training Workshop on Forest Biodiversity, Kuala Lumpur, Malaysia