Exam 20: Developmental Genetics

Segmentation genes in Drosophila act in which of the following orders?

In limb-positioning in tetrapods, the _______ acts as an organizer to promote digit formation at the distal ends of limb buds.

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

What term describes the process by which a cell acquires a certain fate from its neighboring cell?

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

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

The process by which the presence and activity of neighboring cells determine an aspect of development is called ________.

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

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

What substance, in different concentrations, directs developmental fates?

An embryonic stem cell has the potential to differentiate into any cell or tissue type. Is it differentiated, pluripotent, or totipotent?

The establishment of the axes of the body plan occurs during which stage of Drosophila development?

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

If a cell from the blastoderm of the Drosophila embryo is committed to form part of an abdominal segment of the adult, such as the sixth one, and this cell is transplanted into the thorax-committed region of another embryo, will it develop properties of a thoracic or an abdominal segment?

Aniridia is a human condition in which the eye has no iris. The protein encoded by the gene responsible for aniridia is very nearly identical to the protein product of the fly Eyeless protein. What experiment could provide evidence that the two genes are functionally equivalent?

During the evolution of development in animals, it is found that many regulatory genes have been co-opted for the development of different structures, such as limbs or digits. This is an example of what current area of research?

Most of the genes controlling development encode either signal molecules or ________.