Question

For many generations, the following genotypic frequencies were observed in a large population of dinosaurs: 4 percent AA, 32 percent Aa, and 64 percent aa. The climate changed abruptly and resulted in the death of all homozygous recessive dinosaurs (s = 1). In the next generation, the recessive homozygotes died shortly after birth. What percentage of these newborn dinosaurs died? Show Calculation
A) 4% B) 8.5% C) 19.7% D) 36.8% E) 44%

Answer 1

Answer:

C) 19.7%

Explanation:

The new population distribution after climate change wiped out homozygous recessive dinosaurs is:

$AA = \frac{4}{4+32}=\frac{1}{9}$

$Aa = \frac{32}{4+32}=\frac{8}{9}$

The percentage of offspring of this new population that are homozygous recessive is given by:

$P(Aa\ x\ Aa) = \frac{8}{9} *\frac{8}{9} =\frac{64}{81} \\P(aa) = \frac{1}{4}\\P(Aa\ x\ Aa) \cap P(aa) = \frac{64}{81}*\frac{1}{4} =0.197=19.7\%$

19.7% of these newborn dinosaurs died