Exam 18: Developmental Genetics

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

In Drosophila,what is the order of function of the segmentation genes?

It is often said that development is a two-step process.What two steps are likely to be referred to here?

Three investigators-Nüsslein-Volhard,Wieschaus,and Lewis-won the Nobel Prize for physiology and medicine in 1995 for work they did in 1970 with Drosophila.Briefly describe their findings.

Immediately after fertilization of a Drosophila egg,the zygote nucleus undergoes a series of divisions.Subsequent nuclear migration generates a(n)________.

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

Genetic involvement in development appears to be achieved,at least in part,by variable gene activity.

What is the general order of genes involved in determining early Drosophila development?

How does determination relate temporally to differentiation?

Do Hox gene clusters exist in humans? If so,how many are known to exist?

Design an experiment that would allow you to determine if a particular nucleus in a Drosophila embryo is capable of directing development of an entire new fly.

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

In Drosophila,maternal-effect genes are influential in determining the anterior-posterior organization of the developing embryo.

Molecular/structural orientations (gradients)in an egg are thought to play a significant role in development.What is the origin of such gradients? What evidence indicates that the maternal genotype is involved in providing such gradients?

Define determination and differentiation.

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?

A gene that specifies the fate of a particular anatomical segment in Drosophila is called a(n)________.

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

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

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?