Question

For each statement below, indicate if it is TRUE or FALSE and explain why.

(a) All highly conserved stretches of DNA in the genome are transcribed into RNA.

(b) To find functionally important regions of the genome, it is more useful to compare species whose last common ancestor lived 100 million years ago rather than 5 million years ago.

(c) Most mutations and genome alterations have neutral consequences.

(d) Proteins required for growth, metabolism, and cell division are more highly conserved than those involved in development and in responding to the environment.

(e) Introns and transposons tend to slow the evolution of new genes.

Answer 1

ANSWER:

a) False: Many highly conserved stretches of DNA are not transcribed, but instead contain information critical for regulating where and when genes are expressed.

b)True: Species that diverged recently have many identical stretches of DNA sequence by chance, whereas sequence similarity between species that diverged long ago is probably due to functional constraints. The sequences that are necessary to preserve the function of the gene will not be able to undergo changes and thus are more likely to be similar between species that diverged long ago.

c)True. Most genomic changes do not alter the amino acid sequence of proteins or the regulatory properties of genes. Even some mutations that cause minor alterations have little effect on protein function.

d) True. All organisms need to perform a similar basic set of fundamental functions, such as those for metabolism, protein synthesis, and DNA replication. Proteins involved in these functions are shared by descent, and their evolution is constrained.

e)False. Introns and transposons can act as sites where recombinational crossovers occur. Transposons can also catalyze genetic rearrangements. Rearrangements within these sequences are less likely to be detrimental than those occurring elsewhere in the genome.(rate if answer is helpful thanks)