Genetic biodiversity

what is genetic biodiversity?

• the more alleles present in a population, the more genetically diverse the population is

what are species with greater genetic biodiversity more likely to do?

• more likely to adapt to changes in the environment

what factors increase genetic biodiversity and why?

• mutations

• interbreeding between different populations (gene flow)

both these factors will result in an increase in the number of alleles in the population

what is gene flow?

alleles being transferred between populations

how is genetic biodiversity decreased?

• reduced by factors which prevent random mating

• number of alleles in population is reduced

what are some factors that reduce the number of alleles in the population and so genetic biodiversity?

• selective breeding

• captive breeding

• cloning

• genetic bottlenecks

how does selective breeding reduce genetic biodiversity?

only individuals with ‘desirable’ traits are allowed to breed

how does captive breeding reduce genetic biodiversity?

• zoos may only have a small number of captive individuals of a species available for breeding

• zoo keepers select breeding

• this makes a smaller gene pool

how do genetic bottlenecks cause a decrease in genetic biodiversity?

• genetic biodiversity can be reduced by a sudden decrease in population size, and the resulting loss of alleles

what are polymorphic genes?

genes that have more than one allele

are all genes polymorphic?

• no

• most only have one allele (monomorphic) e.g. genes for structural proteins

what can be a measure of genetic biodiversity?

• the proportion of polymorphic genes within a genome can be used as a measure of genetic biodiversity

• higher proportion of polymorphism = higher genetic biodiversity

what is the formula to figure out proportion of polymorphic gene loci?

proportion of polymorphic gene loci = number of polymorphic gene loci / total number of loci