Question

In cattle, a single gene with two alleles determines fur color. The fur can be red, white, or roan. Roan fur has both red and white hair. Which of the following is true about alleles for fur color in cattle?

The allele for roan fur color is dominant over red and white fur color.
The allele for red fur color is dominant over white and roan fur color.
The roan and white alleles are expressed independently of the other.
The red and white alleles are expressed independently of the other.

Answer 1

Am I right with D? Or is it B?

Answer 2

@az

Answer 3

@snowflake0531

Answer 4

So essentially, this is an example of codominance

There's a gene with 2 alleles

so imagine
R is red
W is white

if you had RR you would get red
if you had WW you would get white
but if you have RW or WR then you would get this Roan which has both red and white hair

the common example of codominance that is given is blood types

codominance isn't like incomplete dominance
incomplete dominance is where it mixes

so if you had two alleles for a flower, an allele for it to be red or an allele for it to be white
and you get the red and white allele, then because of incomplete dominance you would have a pink flower

if it was codominance, then your flower would be red AND white

Answer 5

so does that help you decide whether it's D or B with confidence now?

Answer 6

Hmm, yeah, so based on that, it would be D?

Answer 7

yup

Answer 8

Thank you

Answer 9

You're welcome!