Question

the couple is also concerned about their child inheriting hemophilia, another rare disease, which is x-linked. natalie’s brother, daniel’s father, and daniel’s sister both have hemophilia. no one else in either family has the condition. the probability that natalie and daniel’s first child has hemophilia is 1/8.

Answer 1

Hemophilia is a recessive X-linked condition and is inherited from parents. . The probability that Natalie and Daniel’s first child has hemophilia is 1/4, not 1/8. The statement is false.

What is an X-linked gene?

When talking about sex-linked genes, we refer to all those genes located in one of the sex-chromosomes and not in the somatic ones.

X-linked genes are the genes located specifically in the X sex chromosome.

Traits coded by these genes are inherited. This is, X-linked genes are transmitted from parents to children through generations.

According to this, X-linked genetic disorders will be inherited as well.

• Men have a high probability of being affected since they only have one copy of the X chromosome.

• In women, the effect of the mutation might be musk in heterozygous state if the mutation is recessive.

Hemophilia is a recessive X-linked disorder, which means it is coded by the recessive allele.

• X+ ⇒ X chrosomosome with Dominant allele

• X- ⇒ X chrosomosome with Recessive allele

Genotype              Phenotype

X+X+                   Healthy woman

X+X-                    Healthy carrier woman

X-X-                     Hemophilic woman

X+Y                      Healthy man

X-Y                       Hemophilic man

Let us make a pedigree of these families,

Natalie's family:

Mother         healthy carrier          X+X-

Father          healthy                      X+Y

Brother        hemophilic                X-Y  

Natalie         Healthy                     X+X- or X+X+  

Natalie has 1/2 chances of being carrier X+X- and 1/2 of being X+X+.

Daniel's family:

Mother         healthy carrier          X+X-

Father          hemophilic                X-Y  

Sister           hemophilic                X-X-

Daniel          Healthy                      X+Y

He has 1/2 chances of being healthy X+Y and 1/2 of being affected X-Y.

According to the product probability rule, if events A and B are independent from each other, the probability of occurrence of both events together is

P(A∩B) = P(A) x P(B)

In this case,

• event A is Daniel being affected ⇒ 1/2
• event B is Natalie being carrier ⇒ 1/2

P(A∩B) = P(A) x P(B) = 1/2 x 1/2 = 1/4

The probability that Natalie and Daniel’s first child has hemophilia is 1/4, not 1/8. The statement is false.

You can learn more about X-linked genes at

brainly.com/question/12420228

brainly.com/question/14704182

brainly.com/question/1387724

#SPJ1