Biology question?

[carly :]]

1.A cross between a purebred animal with red hairs and a purebred animal with white hairs produces an animal that has both red hairs and white hairs. What type of inheritance pattern is involved?

2.If a white-eyed male fruit fly were crossed with a heterozygous red-eyed female fruit fly, what ratio of genotypes would be expected in the offspring?


can you explain to me how I would answer these?

[kiddietyte]

1) For number one, you need to know the basic inheritance patterns. The three main ones are: dominant/recessive, incomplete dominance, and codominance.

-In dominant/recessive inheritance, one trait is completely dominant over another. This means that there are only two phenotypes; in the event that an individual is heterozygous for the trait, they will exhibit the dominant phenotype.

-In incomplete dominance, one trait is incompletely dominant over another; thus, when one is heterozygous, they will have a trait that is in the MIDDLE of the two other traits. For example, a bunny who is heterozygous for the incompletely dominant trait of black/white fur will have gray fur.

-In codominance, one trait is not dominant over the other. So, when an individual has a codominant trait, they will show both homozygous phenotypes for the trait. For example, if the bunny stated above is heterozygous for black/white fur trait that is codominant, they will have both black and white furs.

In this case, your answer would be codominance.

2) For number two, you need to make a punnett square and cross the two fruit flies. You will then get the results and you can then determine the ratio.

Red eyes are dominant to white eyes (because the female is heterozygous yet displays only red).

Let R = red, r = white; female = Rr, male = rr

Cross it: Rr x rr
.......R........r
r....Rr......rr
r....Rr......rr

You get 1/2, or 50% Rr, and 1/2 or 50% rr.

Your genotypic ratio would be 1 Rr : 1 rr.

[kiddietyte]

1) For number one, you need to know the basic inheritance patterns. The three main ones are: dominant/recessive, incomplete dominance, and codominance.

-In dominant/recessive inheritance, one trait is completely dominant over another. This means that there are only two phenotypes; in the event that an individual is heterozygous for the trait, they will exhibit the dominant phenotype.

-In incomplete dominance, one trait is incompletely dominant over another; thus, when one is heterozygous, they will have a trait that is in the MIDDLE of the two other traits. For example, a bunny who is heterozygous for the incompletely dominant trait of black/white fur will have gray fur.

-In codominance, one trait is not dominant over the other. So, when an individual has a codominant trait, they will show both homozygous phenotypes for the trait. For example, if the bunny stated above is heterozygous for black/white fur trait that is codominant, they will have both black and white furs.

In this case, your answer would be codominance.

2) For number two, you need to make a punnett square and cross the two fruit flies. You will then get the results and you can then determine the ratio.

Red eyes are dominant to white eyes (because the female is heterozygous yet displays only red).

Let R = red, r = white; female = Rr, male = rr

Cross it: Rr x rr
.......R........r
r....Rr......rr
r....Rr......rr

You get 1/2, or 50% Rr, and 1/2 or 50% rr.

Your genotypic ratio would be 1 Rr : 1 rr.

[Dr Knight M.D]

1. This is monohybrid codominace
2. 1 : 1 ratio

[BrownXhardcoreX]

1) codominance
2) ?

Hope that helps!