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B2 Gene 12/1 Lec 7
B2 Gene 12/1 Lec 7 Population Genetics
Question | Answer |
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What is the Hardy-Weinberg Equilibrium | p = frequency of dominant allele//q = frequency of recessive allele//p + q = 1//(p + q)2 = 12//p2 + 2pq + q2 = 1/ p2 = frequency of homozygous dominant (AA)//2pq = frequency of heterozygotes (Aa)//q2 = frequency of homozygous recessives (aa) |
In a certain region of Africa, 16% of the population has sickle cell disease. What percent of the population are carriers (have sickle cell trait)for this allele? What percent of the population will be homozygous for the normal hemoglobin allele? | p + q = 1//q2=.16 thus q=.4//p +.4 = 1 thus p=.6//p2 + 2pq + q2 = 1//2pq-carriers thus 2(.6*.4)=.48//p2-homozygous dominant (normal hemoglobin allele) thus (.6*.6)=.36 |
What is assortative mating? | the tendency to marry based on shared characteristics >> height, intelligence, ethnicity, etc |
What is consanguinity? | marrying of blood relatives |
What are the two ways that natural selection works for or againist an allele? | lethal traits, where allelic frequency should decrease// heterozygote advantage, where carriers may have increased fitness against certain pathogenic conditions, thus increasing allelic frequency |
What is founder effect? | when all individuals of a population are descended from a relatively small number of ancestors, one of whom had a rare allele examples: polydactly among certain Amish groups or albinism among Hopi Indians |
What is heterozygote advantage? | describes the case in which the heterozygote genotype has a higher relative fitness than either the homozygote dominant or homozygote recessive genotype. This favoring is one of the mechanisms that maintain polymorphism and explain genetic variability. |
nonrandom mating _________ the incidence of selected alleles? | increases nonrandom mating increases the incidence of selected alleles? |
In the Hardy-Weinberg Equilibrium what does 2pq represent? | 2pq = frequency of heterozygotes (Aa)//p2 +2pq + q2 = 1 |
In the Hardy-Weinberg Equilibrium what does p2 (p squared) represent? | p2 = frequency of homozygous dominant individuals (AA)//p2 +2pq + q2 = 1 |
In the Hardy-Weinberg Equilibrium what does q2 (q squared) represent? | q2 = frequency of homozygous recessive individuals (aa)//p2 +2pq + q2 = 1 |
In the Hardy-Weinberg Equilibrium what does p represent? | p = frequency of dominant allele//p+q=1 |
In the Hardy-Weinberg Equilibrium what does q represent? | q = frequency of recessive allele//p+q=1 |
When does the Hardy-Weinberg Equilibrium not work? | When natural select, consanguinity, assortative mating/non-random mating, and/or small population size is present |
Changes in allelic frequencies significantly vary generation to generation more so in large or small populations? | In small populations. This is because in small populations each allele is more susceptible to change. |
What is an allele | an alternative form of a gene (one member of a pair) that is located at a specific position on a specific chromosome |
Do some alleles have higher likelihood of de novo mutation? | yes |