Exam 20: Developmental Genetics

The maternal effect bicoid protein is a transcription factor that binds to the promoter of a zygotic gene to activate its expression. What is this second gene?

Which structure in plants acts most like embryonic stem cells in animals?

In Drosophila and other animals, Hox genes encode transcription factors that control development; but in Arabidopsis, a different family of transcription factors is produced with a different set of conserved amino acids. These are encoded by what group of genes?

Human Hox genes are in four clusters: HOXA, HOXB, HOXC, and HOXD, for a total of 39 genes. Besides conserving the clustering of genes, evolution has also conserved __________.

Molecules whose concentration and position in an embryo determine some aspect of development are called ________.

In some forms of cancer, the expression of certain homeotic genes has been altered. Is this more likely to be a cause or an effect of the cancer? Explain.

Holoprosencephaly is a highly variable condition in mammals, including humans. Its effects range from an absence of brain areas, mid-face disorders, and cyclopia to slight dental abnormalities. One form, HPE3, is caused by Shh mutations. Familial cases are inherited as dominants. Which of the following do you expect?

The Antennapedia complex and the bithorax complex of genes all encode transcription factors that have a 180-bp DNA-binding domain. What is this domain called?

Cell autonomous genes affect only those cells in which they are expressed. Which group of early developmental genes are not cell autonomous?

As a Drosophila larva molts and becomes a pupa, most of the larval tissues die and adult structures are formed from cells in clusters known as imaginal discs that have remained unchanged throughout the larval stages. Therefore, the disc cells are __________.

Homeotic genes in virtually all animals are said to show colinearity between the spatial arrangement of the tissues they act on as well as what other feature?

What genetic evidence can demonstrate that some developmental events are due to chemical signaling?

What are Hox and MADS genes, and what do they have in common?

Drosophila mutations such as bcd, if homozygous in the mother, produce offspring with lethal defects, no matter what the genotype of the offspring. For some other genes, the mutant phenotype can be "rescued" by introducing a wild-type allele. What is the reason for these different outcomes?

In Arabidopsis thaliana, a model organism in plant genetics, there are three classes of genes that control the development of floral structures: A, B, and C. Mutations of these genes cause organs to form in inappropriate places. What category of genes are they?

What is the name of the Drosophila multinucleated cell formed early in development?

Which of the following is not a mechanism of differentiation?

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

A homeotic mutant flower has an arrangement (from outside in)of carpels, stamens, stamens, carpels instead of the usual sepal, petals, stamens, carpels. In general, Class A genes specify sepals, Class A and B genes specify petals, Class B and C genes specify stamens, and Class C specifies carpels. This mutant must therefore have a mutation in __________.

Which of the groups of early developmental genes in Drosophila act across segment boundaries to produce parasegments?