Question

Foxglove flowers come in three main color patters as shown below and are the product of dominant epistasis between two genes. The first genes D makes a purple pigment that appears either dark purple (D_) or light purple (dd). The second gene W confines the pigment to small spots on the trumpet-like flower in flowers with genotype W_. In these spots the pigmentation is so intense that one can’t distinguish dark purple spots from light purple spots, so flowers simply appear spotted. Flowers with genotype ww have pigmentation throughput the flower.

A cross is made between a spotted floxglove plant and one with light purple flowers. You count 52 spotted flowers, 25 light purple and 27 dark purple plants among the offspring. What was the genotype of the crossing partners?
a. DdWw and Ddww

b. DDww and ddWW

c. DdWw and DdWw

d. DdWw and ddww

e. Ddww and ddWw

Answer 1

The answer is D as in dominant epistasis the gene for one dominant character hide the other character.

Now the cross is said to be between spotted foxglove plant × light purple flower

Now for light purple flower to be seen the genes should be ddww as w gives light purple colour and d do not cause any problem in show of colour.

For spotted foxglove flower the result is half sppoted and half unspotted flower means the cross is between Ww ×ww. And for the dark purple colour to appear it should be Dd accordimg to result.

Hence the cross is between

WwDd × wwdd