Genetics & Wildlife We are currently in the sixth great mass extinction – ~10 – 20% of species at risk in the next 100 – 200 yrs This is in part as a result of the major rain forest destruction Rain forests cover 7% of the earth - and have 50% of all species, half is already gone Losing 1-2%/yr – could be all gone in 150yrs Meaning we are suffering large-scale genetic erosion
Conservation geneticists need to identify: –ESU (Evolutionary significant unit) – Species –Subspecies/unique geographic areas/hotspots – Establish phylogeographic patterns to predict future population migrations – Counter genetic erosion Genetics & Wildlife
The greatest threat to a species is populations size Inbreeding which leads to loss of heterozygosity homozygosity Accumulation of deleterious mutations –recombination can no longer purge mutations when its homozygous –Expression of recessive deleterious alleles – Fitness It takes 5 generations to homozygosity Ralls et al. 1988; Cmokrak & Roff 1999; Saccaheri et al. 1997 Genetics & Wildlife Factors that influence evolvability
How small does a population have to be before it starts down the extinction vortex The MVP Minimum Viable Population size – The smallest number of individuals needed to sustain genetic variation Population viability analysis (PVA) – Predicting whether or not a species will survive over time Genetics & Wildlife How small is too small?
In a small population several factors come into play: Genetic drift: Loss of genetic alleles over time Genetics & Wildlife
A special case of drift is The Founder Effect: – Loss of genetic variation in space Genetics & Wildlife
Organisms must constantly evolve and adapt to survive in a dynamic environment, as they compete with ever-evolving opposition (pathogens, parasites and predators) – Small populations lack adequate genetic variation to keep up with the pace Genetics & Wildlife The red queen hypothesis
Microsatellites: small repeat sequences – Non-coding fragments - mutation rate = rapid sorting of alleles SNP’s: single nucleotide polymorphism – Found throughout entire genome (mtDNA, nulcear, Y chromosome) 53 558 214 SNP’s in human listed 2012 – Mardis 2011 Genetics & Wildlife Measuring genetic variation
With Next Generation Sequencing Ecosystem level – eDNA – soil, water – debris filtered from air – Technique: Metabarcoding: species identification What is Barcoding? – short / genetic marker – plus voucher specimen information Genetics & Wildlife Measuring genetic variation
Biogeography – Describe evolutionary history – Evolutionary significant units Significant sequence divergence at mtDNA and nuclear DNA level – Management units Significant sequence divergence at mtDNA level Genetics & Wildlife Measuring genetic variation
Your consent to our cookies if you continue to use this website.