Genetics Question

[tksm8727]

Would anyone be able to answer the following question and provide an explanation:

You have 6 pure breeding (homozygous) yellow flowered mutants (labelled A to F) of a plant that normally has red flowers.

When you cross plant A with either B or E the F1 have yellow flowers but A crossed with C,D, or F produces red flowers F1.

When you cross plant D with F the F1 have yellow flowers but D crossed with any other plant produces red flowered F1.

When you cross C with any other plant you always get red flowered F1.

These data provide evidence that there are ___X___genes controlling flower colour in this sample of mutants.

a. X=5

b. X=4

c. X=3

d. X=2

e. There is insufficient data to determine X

?????

Any help with this question would be appreciated...thank you

[rommel]

You need to draw this all out and I dont have paper here...but if they are yellow and that is mutant then they are rr if RR or Rr is the Dominant red color. So you know that

A x B --> yellow

A x E --> yellow

 

My initial reaction is I don't understand how you worded the question because if A to F are yellow and that is mutant then provided that yellow mutant is a recessive type you can't ever get red back by crossing within. The yellow must be part of a heterozygous condition to obtain red results after...unless I misread it. Check and repost if this is the exact quesiton....becuase if so you have to play with other combinations

[tksm8727]

Thanks for the reply.

I checked and this is how the question is worded.

The question comes from practice exam questions posted by my prof in preparation for our midterm on the weekend.