Entrance Exams
Govt. Exams
The wobble hypothesis explains how changes in the third codon position often don't change the amino acid due to the degeneracy of the genetic code, resulting in silent mutations.
Frameshift mutations shift the reading frame for all downstream codons, typically resulting in nonfunctional proteins or premature termination.
Frequency of heterozygotes = 2pq = 2(0.6)(0.4) = 0.48 in Hardy-Weinberg equilibrium.
Mutations are random, non-directed changes in DNA that provide genetic variation for natural selection to act upon. They're not inherently harmful or beneficial.
Industrial melanism is a classic example of directional selection where environmental change (pollution) favors one phenotype (dark color) over another.
Inbreeding increases homozygosity and decreases heterozygosity. The relationship is: Ht = H0(1-F), where heterozygosity decreases with increasing F.
In cave environments, eyes provide no selective advantage. Neutral mutations affecting eye development accumulate through genetic drift, resulting in eye loss.
If q² = 0.01, then q = √0.01 = 0.1. This is the frequency of the recessive allele.
Peripatric speciation occurs when a small population is geographically isolated, genetic drift acts strongly, leading to reproductive isolation and speciation.
In a normal test cross (Aa × aa), expected ratio is 1:1 (50% each). 40% dominant suggests some homozygous dominant (AA) offspring are dying, indicating lethal homozygous dominant allele.