Exam 20: Developmental Genetics

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

In the development of C.elegans,an embryo of 1090 cells then loses 131 cells.This is an example of what process?

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

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

There is much controversy in the newsboth scientific and popularabout the use of embryonic stem cells for research.These cells are grown as cell lines in culture,created by taking the inner cell mass from 5-day-old embryos.What is the center of the controversy?

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

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

A mutation in a fly causes an antenna to develop where a leg should be.This is an example of a ________ mutation.

Certain mutations in non-Hox genes actually produce homeotic mutants due to a failure to modulate chromatin acetylation appropriately.This influence on cellular "memory" is called what?

An Antennapedia (Antp)mutant in Drosophila has legs in place of antennae.This is caused by

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?

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?

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

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?

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

What characteristic of a cellular blastoderm in Drosophila embryogenesis distinguishes it from the syncytial blastoderm?

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

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

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.

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