Exam 13: The Genetic Control of Development

The class of genes required for establishing the anteroposterior axis is the:

What characteristics allowed Drosophila melanogaster (an insect)to emerge as the leading genetic model of animal development?

A Drosophila researcher recently isolated a number of mutant fruit flies.The phenotype of each mutant is described below (i-iv).For each mutant,describe the type of gene (maternal-effect gene,gap gene,segment-polarity gene,or homeotic gene)that was most likely the cause of the altered phenotype. (i)Homozygous mutant females appear phenotypically normal but produce larvae that have two posterior ends. (ii)The flies contain four wings rather than two. (iii)The wings are oriented backward. (iv)The flies are missing two pairs of legs due to a shortened thoracic region.

There are ______ Hox genes in the laboratory mouse.

In the developing Drosophila embryo,the Hox genes are expressed:

The pre-mRNA for Sex-lethal,transformer,and doublesex are:

The genes required for proper organization of the anteroposterior body axis of the fly embryo are grouped into how many classes?

The nematode worm Caenorhabditis elegans is comprised of approximately ______ somatic cells.

In the developing chick vertebral limb bud,the zone of polarizing activity (ZPA)organizes a pattern along the anteroposterior axis.Transplantation of the ZPA from a posterior to anterior position:

The class of genes required for establishing the formation of a contiguous block of segments is the:

All eight Drosophila Hox genes encode proteins containing a highly conserved 60-amino-acid domain called the:

The homeotic,gap,pair-rule,and segment polarity genes all control:

The doublesex (dsx)gene plays a central role in governing the sexual identity of somatic (non-germ-line)tissue.Null mutations in dsx cause:

In homeotic mutants:

A morphogen is a molecule that induces:

Homeosis is defined as the failure to: