. A Drosophila transgene has coding sequences for GFP positioned downstream of a

Question

. A Drosophila transgene has coding sequences for GFP positioned downstream of a 7-kb DNA fragment taken from the segment-polarity gene wingless (wg). In Drosophila embryos, the transgene expresses GFP fluorescence in exactly the same pattern as Wg. Crosses are used to place the transgene in different mutant backgrounds. a. Describe, with words and diagrams, the pattern of GFP fluorescence you expect to see in each of the following types of embryos if they are examined at germ-band extension.

i. wild-type

ii. embryos laid by a mother who lacks the function of the maternal-effect gene bicoid

iii. embryos that lack the function of the pair-rule gene even-skipped

iv. embryos that lack the function of the segment-polarity gene engrailed

v. embryos having a mutation in the Hox gene Ultrabithorax that leads to a homeotic transformation of T3, the third thoracic segment which normally has a haltere, to T2, the second thoracic segment which normally has a wing.

Explanation / Answer

i. Wild Type:
The allele that encodes the phenotype most common in a particular natural population is known as the wild type allele. It is often designated in genetic shorthand as "+". Any form of that allele other than the wild type is known as a mutant form of that allele.

Related Questions

Navigate

• Browse (All)
• Browse #
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.