Anthro notes - Anthro 9/23 lecture Conditions for natl...

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Anthro 9/23 lecture Conditions for nat’l selection -variation in trait -heritability of trait -correlation w reproductive success (problems w society and contraception today) soures of variation -1mutation (ultimate source of variation) -2meiosis (crossing over. .recombining DNA) -3independent assortment and 4segregation (of chromosomes) ind assortment—segregation of a pair of chroms doesn’t affect prob of seg for other pairs of chroms -law of segregation—sex cells contain 50% of chromosomes trisomy---out of 23 pairs of chromosomes, only trisomy 21,18, and 13 survive population genetics- how is a trait distributed across populations? Highest frequency of trait is a good indicator as to where mutation originally occurred Hardy Weinberg equation----- 1/500 african, 1/1200 hispanic—sickle cell SS carriers Law of PROBABILITY-interested in allele and genotype frequency 1/500 in US have disease= .002= prob of being SS in USA ---SS = q squared p, q are alleles sq root of .002=.045 1-q=p p=.995 chance of being AS carrier=2pq=.09 or 9% --------------------------------------------------------------------------------------------------- LECTURE 9/28/09 POPULATION—a community of potentially interbreeding individuals at a given locality BOUNDARIES -geographic, socio-cultural (ex- city, tribe) [language, space is boundary) GENE POOL All of the genes present in a population
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Q (in hardy-weinberg) ALWAYS REFERS TO RECESSIVE or to second in alphabet Allele frequency--- #p/total alleles, #q/total alleles Chance of being homozygous (allele freq) (allele freq) =m squared Assumptions of Hardy Weinberg---- -lab work OK -sample was representative of the population -random mating -no evolutionary forces (gene flow, natl selection, mutation, drift) populations evolve, not individuals---see this through change in allele frequencies gives us a way to ask: are alleles arranged according to the laws of probability? Gives us way to predict: Genotypes of the next generation Carrier=heterozygote LECTURE 9/30/09 Assortative mating --not random --negative or positive----(either brown mates w brown or brown always mates with tan) -- not a force of evolution (no change in allele frequency) -positive phenotypic assortative mating --positive genotypic assortative mating (inbreeding increases homozygosity) (homozygous alleles spread rapidly because they’re in small population) --polygamy—polygny—one male may have a greater contribution to the gene pool microevolution --changes in frequency of alleles from generation to generation allele frequencies change bc of mutation, gene flow, natural selection, loss of alleles due to genetic drift GENETIC DRIFT—random change in allele frequency from one generation to the next (occurs during meiosis) -leads to the reduction of variation within a population -given time and population size
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Bottleneck and Founder effect--- loss of variation because of drastic reduction in population size -new population coming after population will be significantly different
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Anthro notes - Anthro 9/23 lecture Conditions for natl...

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