Chapter 20

Define duplication:

Answer explanation

A region of a chromosome that is present twice instead of once.

Define deletion:

Answer explanation

A missing region of a gene or chromosome.

Deletions or duplications that include the centromere, the site associated with attachment of the spindle fibers that move the chromosome during cell division, are _____ observed.

• always

• usually

• sometimes

• rarely

The process of creating new genes by duplication followed by change in sequence over evolutionary time.

• duplication

• divergence

• duplication and divergence

• neither duplication or divergence

Multiple rounds of duplication and divergence can give rise to a group of genes with related functions known as a

• gene pool

• gene family

• allele frequency

• genotypic rate

A region along a DNA molecule in which many duplicated copies of a short sequence of nucleotides are adjacent to one another.

Answer explanation

tandem repeat

The reversal of the normal order of a block of genes is known as an _____. An ______ is typically produced when the region between two breaks in a chromosome is flipped in orientation before the breaks are repaired. Especially in large genomes, the breaks are likely to occur in noncoding DNA rather than within a gene.

Answer explanation

inversion

Why are germ-line mutations more important in evolution than somatic ones?

Answer explanation

Germ-lne mutations are passed on to the next generation but somatic mutations are not. Evolution is change in genetics of populations from gen. to gen,.

Why is recombination critical to generating genetic variation?

Answer explanation

recombination shuffles mutations into new permutations

What does it mean to say that an allele is “fixed” in a population?

Answer explanation

IF there is only one allele for that gene in the population, its frequency is 1 (100%)