Exam 23: Developmental Genetics

Which term refers to the regulatory events that establish a specific pattern of gene activity and developmental fate for a given cell?

C.elegans is used as a model organism in the study of the Notch signaling pathway.What is the method communication between cells in the Notch signaling pathway?

Flowers that develop in Arabidopsis originate from concentric rings of cells.What class of genes is responsible for the development of sepals?

Mutations that eliminate a contiguous region in the Drosophila embryo's segmentation pattern are called_______ .

Over the course of evolution,humans have obtained four Hox gene clusters due to duplication.The presence of multiple Hox gene clusters suggests what?

Mutations in the selector genes sometimes form structures in the wrong segment,transforming the antenna of a fly into a leg,for example.What are such mutations called?

After fertilization of an egg the totipotent cell divides and the cells begin to specialize.These 30-40 cells are called_______ and are pluripotent.

What is the significance of the homeodomain?

It is presently believed that the asymmetric distribution of substances in the egg,positioned by the mother,is responsible for establishing the determined state.Which general term describes such molecular positioning?

A gene that specifies the fate of a particular anatomical segment in Drosophila is called an_______.

From a human developmental standpoint,what is the significance of Hox genes?

What kinds of general observations cause one to conclude that development is the result of variable gene activity?

In most species the expression of Hox genes is colinear with the anterior to posterior organization of the organism.Describe what this means.

Provide a brief description of the variable gene activity hypothesis as it relates to development.What information is often provided in support of this hypothesis?

Which of the following is a fundamental characteristic of the Notch pathway?

In what order do the segmentation genes function in Drosophilia?

Which general genetic process is believed to account for the variety of cellular structures and functions in eukaryotic cells?

How does determination relate temporally to differentiation?

Which class of genes controls the developmental identity of segments along the anterior-posterior axis?

Maternal effects are cases of extrachromosomal inheritance in which the genotype of the mother influences the phenotype of her immediate offspring in a non- Mendelian manner.Provide a rationale for the molecular basis of a maternal effect.