Question

Consider 2 genes in peas- gene controlling seed color- yellow Vs green; gene controlling seed texture-smooth Vs wrinkled. Assume the two genes are very tightly linked. A true breeding smooth green plant is crossed to a true breeding wrinkled yellow. All the F1 progeny were smooth yellow. The F1 generations were self-fertilized. In the F2 what is the expected ratio of the phenotypes- Smooth & yellow: smooth & green: wrinkled & yellow: wrinkled & green

Answer 1

Answer:

Smooth & yellow: 9

smooth & green: 3

wrinkled & yellow: 3

wrinkled & green: 1

Explanation:

Gene controlling seed color are yellow Vs green

Gene controlling seed texture are smooth Vs wrinkled

In F1 generation, A true breeding smooth green plant (SSyy) is crossed to a true breeding wrinkled yellow (ssYY)

Off spring in F1 generation are smooth yellow (SsYy)

This means smooth texture is dominant over wrinkled texture and yellow color is dominant over green  

in F2 generation, the cross is carried between SsYy

SY         Sy        sY          sy

SY SSYY SSYy SsYY SsYy

Sy SSYy SSyy SsYy Ssyy

sY SsYY SsYy ssYY ssYy

sy SsYy Ssyy ssYy ssyy

Smooth & yellow: 9

smooth & green: 3

wrinkled & yellow: 3

wrinkled & green: 1