Lab 1 outline

Lab 1 outline - HbS/HbA=mild anemia (BUT malaria resistant)...

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Lab #1 Population Genetics Population Genetics - Definitions Population-Group of individuals of the same species living in the same area Species-Group of individuals able to interbreed Gene pool-All the alleles in a population Gene-Unit of DNA that determines a trait Allele-Different forms of a gene B=brown eyes/b=blue eyes Genotype-Genetic makeup of an organism BB, Bb, bb Phenotype-Physical appearance of an organism Based on genotype and environment Population Dynamics Are populations static? Microevolution Change in a gene pool (change in gene frequency) from one generation to the next What causes microevolution? Small population size Mutation Gene flow Non-random mating Natural selection Recessive Refuge Recessive deleterious alleles (d’s) “hide out” in gene pool for a long time Masked by heterozygotes dd=death DD=normal Dd=normal Heterozygote Advantage Heterozygotes have a selective advantage over homozygotes **Sickle cell anemia in equatorial Africa** HbS/HbS=full blown anemia (die of anemia)
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Unformatted text preview: HbS/HbA=mild anemia (BUT malaria resistant) HbA/HbA=normal (die of malaria) HbS-sickle cell allele HbA-normal allele No advantage where there is no malaria!! Hardy-Weinberg Equilibrium Null/theoretical model Tests if allele frequencies change from one generation to the next Populations NOT undergoing microevolution are in H-W equilibrium H-W Assumptions Infinitely large population No mutation No migration Random mating No natural selection p= dominant allele frequency (A) q=recessive allele frequency (a) ALLELE frequencies: p + q = 1 or f (both alleles) = 1 GENOTYPIC frequencies: p 2 +2pq+q 2 =1 p 2 =% of popln that is homozygous dominant (AA) 2pq=% of popln that is heterozygous q 2 =% of popln that is homozygous recessive (aa) HW Equilibrium When a population is NOT in HWE (BTWall populations are NOT in HWE), then p and q are changing p goes upthen q goes down (or vice versa) and this is microevolution (change in gene frequencies)...
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This note was uploaded on 04/16/2008 for the course BIOL 112 taught by Professor Vaughn during the Spring '08 term at Texas A&M.

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Lab 1 outline - HbS/HbA=mild anemia (BUT malaria resistant)...

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