A dihybrid cross question, please help?

Question

A femal fruit fly with ebony body color (ee) and white eyes (ww) is mated with a male fruit fly with normal body color (EE) and normal eye color (WW).

what would be the phenotype for F1 females and F1 males?

how would I set up an F2 generation Punnet Square??

I want to know how to do the cross for F1 females by F1 males...

Answer 1

I assume you've already figured out that the F1 generation will all be genotype EeWw, phenotype normal.

First, figure out the gametes that your F1 flies will produce:

25% EW

25% Ew

25% eW

25% ew

Then draw up a Punnet Square with four rows and four columns. Put one of each gamete type (one of EW, one of Ew, etc.) at the top of each column, and again at the beginning of each row. I tried to draw this for you but couldn't get the formatting right.

Work out the genotype when each of the gametes combine. You should end up with phenotypes that are 75% dominant phenotype, 25% recessive.

Answer 2

HI!!

For F1 generation: the male gametes formed would be (EW) n(EW)

females gametes would be (ew) n (ew).

Now, the male n female offspring would have the genetic make up as

Males:EeWw    &   EeWw

Females:EeWw  & EeWw

in all off springs male character is dominant.

Now for F2 generation:the males gametes would be (EW),(Ew),(We),(ew) & females gametes would be (EW),(Ew),(We),(ew).

Now these will give 16 off springs with genetic makeup as:

1-EEWW                  9-EeWW

2-EEWw                 10-EeWw

3-EeWW                 11-WWee

4-EeWw                  12-eeWw

5-EEWw                  13-EeWw

6-EEww                   14-Eeww

7-EeWw                   15-eeWw

8-Eeww                    16-eeww

This cross will have 75%dominant character n 25% recessive character.

Now for making punnet square:

make two rows n two columns for F1 generation with  gametes on horizontal n vertical surfaces.

For F2 generation make 4 rows n 4 columns with gametes on horizontal n vertical surfaces.

HOPE THIS WILL HELP U.GL!!!