《人口与资源英》

1、整理课件POPULATION GENETICS 2008 Paul Billiet ODWS整理课件Predictable patterns of inheritance in a population so long asnthe population is large enough not to show the effects of a random loss of genes by chance events i.e. there is no genetic driftnthe mutation rate at the locus of the gene being studied i

2、s not significantly highnmating between individuals is random (a panmictic population)nnew individuals are not gained by immigration or lost be emigrationi.e. there is no gene flow between neighbouring populationsnthe genes allele has no selective advantage or disadvantage 2008 Paul Billiet ODWShttp

3、:/ 衬塑复合管 涂塑复合管 钢塑复合管 消防涂覆钢管整理课件SUMMARYnGenetic driftnMutationnMating choicenMigrationnNatural selectionAll can affect the transmission of genes from generation to generationGenetic EquilibriumIf none of these factors is operating then the relative proportions of the alleles (the GENE FREQUENCIES) wi

4、ll be constant 2008 Paul Billiet ODWS整理课件THE HARDY WEINBERG PRINCIPLE Step 1 nCalculating the gene frequencies from the genotype frequencies nEasily done for codominant alleles (each genotype has a different phenotype) 2008 Paul Billiet ODWS整理课件IcelandPopulationn313 337 (2007 est)Arean103 000 km2Dis

5、tance from mainland Europen970 km 2008 Paul Billiet ODWSGoogle Earth整理课件Example Icelandic population: The MN blood group2 Mn alleles per person1 Mn allele per person1 Mm allele per person2 Mm alleles per personContribution to gene pool129385233Numbers747MnMnMmMnMmMmGenotypesType NType MNType MPhenot

6、ypesSamplePopulation 2008 Paul Billiet ODWS整理课件MN blood group in IcelandTotal Mm alleles = (2 x 233) + (1 x 385) = 851Total Mn alleles = (2 x 129) + (1 x 385) = 643Total of both alleles =1494= 2 x 747 (humans are diploid organisms)Frequency of the Mm allele = 851/1494 = 0.57 or 57%Frequency of the Mn allele = 643/1494 = 0.43 or 43% 2008 Paul Billiet ODWS整理课件In general for a diallellic gene A and a (or Ax and Ay) If the