Exam 18: Organelle Inheritance and the Evolution of Organelle Genomes

In the development of C. elegans, an embryo of 1090 cells then loses 131 cells due to what process?

Mouse eye genes can be inserted into Drosophila and can regulate the flies' eye formation. Differences in the size of horses are controlled by a gene also found to influence size variation in zebrafish. What do these examples illustrate?

Coordinate genes in an organism such as Drosophila determine the ___________ of the early embryo.

Suppose that a homeotic gene from Drosophila is introduced into an Arabidopsis embryo that has a pre- existing mutation in one of its homeotic flower genes. What effect would you expect and why?

In early vertebrate embryonic development, a number of pathways, such as Wnt, Hedgehog, and Notch, regulate differentiation and organ formation. They operate by___________ .

Which of the following is not a mechanism of differentiation?

What substance, in different concentrations, directs developmental fates?

A highly conserved protein domain of 60 amino acids, the homeodomain, is found in a large number of animals. This domain the proteins that have them to bind to what?

In Drosophila, a developmental mutation called ssa (spineless aristapedia) results in flies with mini leg parts on the antennae. What kind of gene does this mutation affect?

Flower homoeotic genes encode:_____________ .

Which group of genes in Drosophila embryos must be mutated if the result is elimination of a significantly sized, contiguous region of segmentation?

Since mice embryos with loss- of- function Hox mutations result in homeotic alterations, then introduction of such a mutation might cause ___________.

Hunchback protein occurs along a gradient, where the anterior embryo has high protein levels and the posterior has low levels, yet the hunchback mRNA is found at the same concentration throughout the embryo. These observations suggest that hunchback must be regulated post-________

Cell signaling during much of C. elegans development occurs along concentration gradients. What kind of signaling does this represent?

The abdominal segments of Drosophila have no appendages. Loss of function of bithorax genes results in appendages forming in these abdominal segments. Therefore,_________ .

Describe the genetic evidence that demonstrates that a developmental gene has maternal effect.

Use a description of C. elegans development to distinguish clearly between differentiation and determination.

Polycomb group (PcG) gene mutants cause ectopic expression of Antennapedia (Antp) and other homeotic genes. The PcG protein encoded by the PgG gene has a domain that binds to methylated histone H3. This finding supports which of the following hypotheses?

Use of double mutants has been invaluable in studying developmental pathways. In C. elegans, sex is determined by the ratio of sets of autosomes to X chromosomes. A diploid male has one X, and diploid hermaphrodites have two X's. The loss- of- function gene her- 1 produces XO worms that are hermaphrodites, but XX worms are unaffected. Mutation of a second gene, tra, causes the XX to develop as male. Given this information, what would be the phenotype of a tra, her- 1 double mutant?

If a cell is no longer able to differentiate into any type of tissue, it has become _________.