question (1 Viewer)

[DepressedPenguino]

Question: The first sex-linked trait discovered was white eye colour in Drosophila, controlled by a recessive allele. This mutation suddenly appeared in pure breeding red-eyed Drosophila stock. (The red eye allele is the dominant)

What would be the phentypic ratios if a heterozygous female fly for this trait were crossed with a red-eyed male fly?

(a) Female: all white-eyed Male: 50% white eyed and 50% red-eyed

(b) Female: 50% white eyed and 50% red eyed. Male: all white eyed

(c) Female: all red eyed Male: 25% white eyed and 75%red eyed

(d) Female: all red-eyed Male: 50% white eyed and 50% red eyed

 

[faisalabdul16]

D

 

[DepressedPenguino]

How do you determine which offspring is female and which is a male? I am using the punnett square btw

 

[faisalabdul16]

Have you done sex linkage?

Female is XX
Male is XY

 

[Queenroot]

R = red (dominant)
r = white (recessive)

XX = female
XY = male

 

[DepressedPenguino]

Oh right.. sex linkage and I forgot that the gene that codes for eye colour isn't located on the Y chromosome! Thank you queenroot and faisalabdul