Answer the following questions about the evolution of human chromosomes, for 10 points each.
[10h] Two answers required. Extra copies of these two structures led scientists to conclude that human chromosome 2 formed from the fusion of two ancestral ape chromosomes. These two chromosomal regions contain large repetitive sequences of satellite DNA.
ANSWER: centromeres AND telomeres
[10e] The fusion of two ancestral chromosomes explains why humans have this total number of chromosome pairs, one less than other primates. This is also the haploid number for humans.
ANSWER: 23
[10m] Due to differentiation of the X and Y chromosomes, this phenomenon only occurs in the pseudoautosomal region. During meiosis, chiasmata are the site of crossing over, a form of this phenomenon.
ANSWER: genetic recombination [or genetic shuffling]
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