A homeotic gene does which of the following?
a. It serves as the ultimate control for prokaryotic operons.
b. It regulates the expression of groups of other genes during development.
c. It represses the histone proteins in eukaryotic chromosomes.
d. It helps splice mRNA after transcription.

Homeotic genes

a. Encode transcription factors that control the expression of genes responsible for specific anatomical structures.

b. Are found only in Drosophila and other arthropods.

c. Are the only genes that contain the homeobox domain.

d. Encode proteins that form anatomical structures in the fly.

What does it mean to say that experimental conditions are controlled? Select True or False for each statement.

T/F The test groups consist of the same individuals.

T/F The null hypothesis is correct.

T/F There is no difference in outcome between the control and experimental treatment.

T/F All physical conditions except for one are identical for all groups tested.

Two eukaryotic proteins have one domain in common but are otherwise very different. Which of the following processes is most likely to have contributed to this similarity?

a. Gene duplication

b. Alternative splicing

c. Exon shuffling

d. Random point mutations

What is a homeotic mutant?

a. An individual with a structure located in the wrong place

b. An individual with an abnormal head-to-tail axis

c. An individual that is missing segments

d. An individual with double the normal number of structures

The human genome size is 3 billion base pairs, and the size of the baker's yeast genome, a single-celled organism, is 12 million base pairs. Therefore, the predicted genome size for another single-celled organism, an amoeba,

a. Is about the size of the human genome

b. Is about the size of the yeast genome

c. Is somewhere between the sizes of the yeast and human genomes

d. Cannot be predicted with any certainty

Below are the amino acid sequences (using single letters; see Figure 5.14) of three short segments of the FOXP2 protein from five species. These segments contain all amino acid differences between the FOXP2 proteins of these species. Compare the amino acid sequences by answering parts (a)–(d).

Chimpanzee: PKSSD ... TSSTT ... NARRD

Mouse: PKSSE ... TSSTT ... NARRD

Gorilla: PKSSD ... TSSTT ... NARRD

Human: PKSSD ... TSSNT ... SARRD

Rhesus monkey: PKSSD ... TSSTT ... NARRD

Circle the names of any species that have identical amino acid sequences for the FOXP2 protein.

a. Chimpanzee, Gorilla, Rhesus monkey

b. Human, Mouse

c. Chimpanzee, Human, Mouse

d. Rhesus monkey, Human, Gorilla

Use a highlighter to color any amino acid that varies among the species. (Color that amino acid in all sequences.)

e. Primates and rodents diverged between 60 and 100 million years ago, and chimpanzees and humans about 6 million years ago. Compare the amino acid differences between the mouse and the C, G, R species with those between the human and the C, G, R species. What can you conclude?