Question

Can someone help me with this question I’m not getting it

Answer 1

Answer:

a. $X^BY$

b. $X^BX^B$

c. $X^{b} Y$

d. $X^BX^b$

e. $X^bX^b$

Explanation:

There are two sex chromosomes, X and Y. A female has two X chromosomes and the male has an X and a Y. The genotype then for male and female woud be:

Female = XX

Male = XY

Now the superscript indicates the allele for a particular trait.

Based on what was given:

H is dominant (no hemophilia)

h is recessive (hemophilic)

B is dominant (no color blindness)

b is recessive (color blind)

As you can see in the given, the Y chromosome has no allele, this means that hemophilia and color-blindness is X-linked or dependent on the X chromosome.

For the first, it says normal male this means that the genotype would be XY , the X chromosome would have the normal dominant allele for color-blindness so that would be B.

$X^BY$

The next one would be homozygous normal female. This means that the female has both dominant alleles on their chromosome (BB)

$X^BX^B$

The third one says colorblind male. Unlike the females, the male chromosomes only need the X to be affected for them to express the trait. So in this case, the X will have the recessive allele for colorblindness (b).

$X^{b} Y$

The foruth one is a normal female for color-blindess but is heterozygous. This means that the female has the recessive allele, but the dominant trait masks it. So it will have both alleles (Bb)

$X^BX^b$

Lastly, a color-blind female would have to have two recessive alleles. This is what we call homozygous recessive (bb).

$X^bX^b$