Drosophila Fly Crosses

[NutMeg91]

In our notes we're looking at Sturtevant's X chromosome study for Drosophila flies. To quote my notes, "Normal, dominant eye color in Drosophila is brick red. White and vermillion are eye color mutations and are recessive. Yellow is a recessive body color. Miniature and rudimentary are recessive wing mutations. The symbols for each are: yellow (y), white (w), vermillion (v), miniature (m), rudimentary (r).

Our homework problem is:
You have a line of Drosophila that have both yellow bodies and vermillion eyes. Show the crosses, using proper symbols, you need to do, to construct a line of flies that have only yellow bodies. Remember that these are both X linked.

I'm stuck on how to start the crosses. Maybe it's because I've been studying all day but I seem to be having a brain block. Any help would be greatly appreciated.
Thanks!

[Cat]

yyvv (yellow bodies and vermillion eyes female) x YV(Wild type male)

All female progeny look wild type: YyVv, all males yv (yellow bodies and vermillion)

YyVv x yv

Some of the females will be yyVv that have only yellow bodies. Some of the males will be yV that have only yellow bodies.

yyVv x yV

yyVV and yyVv females both have only yellow bodies.
yV males have only yellow bodies and yv male that have yellow bodies and vermillion eyes.

Cross each of the females with yV males that have only yellow bodies.

if all of the progeny have only yellow bodies, female must have been yyVV genotype and your line is established.


yy

[merv]

hey, Cat, if she wants it she gotta earn it! use it or lose it! They don't call military helicopters Apathy's.