bio lect 20

bio lect 20 - migration - increases variation witin and...

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bio lect 20 fluctuation of allele frequencies: mutation is source of variation. mutation -coding sequence -genetic regularities -copy number of genes - genome copy - polyploid -2n -> 4n you can affect the phenotype with coat color variation in mice agouti - coding sequence X 1 melanin - increases expression and greatly decreases melanin supressess melanin. - migration - > gene flow nirth -> breeds could be gametes moving most of the gene flow in pants hppenes in the gametes migration has several roles in mutation 1) spread successful mutation migration is what holds species together, they have certain properties hat are shared and derived 2)opposes the divergence among populations due to genetic drift or local selection mutation heavy metals (selection for copper tolerance) frequency of alleles: can give rise to to clines (in alleles or phenotypes frequencies) cline - gradual change of allele frequency over space (EX wind) summarize mutation - increase variation within population over time lose variation within
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Unformatted text preview: migration - increases variation witin and decrease varition amond pop. (genetic) Fitness: relative survival over others-selection acts through teh phentype-survivl and reproduction of one phenotype (genotype) relative to others in the population - often environmentally dependant phenotype distribution F over human height bell curve from short to tall genetic variation environmental varitaion these two interact to give rise of variation in pop. Selection: directional selection - will shift the curve towards the more advantageous (favored) genotype stabilizing selection - results when both extremes are less advantageous and it thins up tyeh curve, teh next generation goes back to normal. no real cange ( no real evolution) maintain variation in population other possibility is where teh ones in teh middle are disadvantageous (disruptive) after selection (many of teh middle ind are taken out and can cause speciation)...
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This note was uploaded on 05/10/2010 for the course BIO 1B taught by Professor Carlson,mischel,power during the Spring '07 term at Berkeley.

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bio lect 20 - migration - increases variation witin and...

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