Question 74

(Multiple Choice)

Chimpanzees,gorillas,and orangutans have DNA sequences that are almost identical to those of humans; however,these genes are found on 24 pairs of chromosomes in apes,while humans have 23 pairs.The C2 chromosome in humans is a large chromosome with similar banding pattern and DNA sequences to two smaller chromosomes in apes (C2 and C4).In addition it appears to have both a vestigial second centromere and telomere sequences in the middle of the strand.
-Why do,in general,do only female cats have the tortoiseshell phenotype?


A)a male inherits only one allele of the X-linked gene controlling hair color
B)the Y chromosome has a gene blocking orange coloration
C)only males can have Barr bodies
D)multiple crossovers on the Y chromosome prevent orange pigment production
E)two tortoiseshell genes located on the X chromosome are required

Answer