X-linked genes are inherited. The affected girl's father is hemophilic (X-Y), and the mother might be either hemophilic (X-X-) or carrier normal (X+X-).
<h3>What are the X-linked genes?</h3>
These are the genes located in the X séx chromosome and not in the somatic ones.
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 disorder 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 heter0zyg0us state.
Hemophilia is a X-linked recessive genetic disorder.
Let us represent the recessive allele with the symbol -, and the dominant allele with the symbol +.
- X- is the chromosome carrying the recessive allele
- X+ is the chromosome carrying the dominant allele
For the affection to be expressed, the person must be either,
If the baby girl is found to have inherited the trait from her parents, then her genotype is X-X-. She must have received one X- chromosomes from each parent.
- Her father provided the X chromosome, so he must be hemophilic (X-Y)
- Her mother provided the other X chromosome, but she can be either a carrier (heter0zyg0us, X+X-) or hemophilic (h0m0zyg0us recessive, X-X-).
Options,
Cross 1) affected father x carrier mother
Parentals) X-Y x X+X-
Gametes) X- Y X+ X-
Punnett square) X- Y
X+ X+X- X+Y
X- X-X- X-Y
F1) 1/2 = 50% of the progeny is expected to be healthy (25% X+X- girls + 25% X+Y boys)
1/2 = 50% of the progeny is expected to be hemophilic (25% X-X- girls + 25% X-Y boys)
Cross 2) affected father x affected mother
Parentals) X-Y x X-X-
Gametes) X- Y X- X-
Punnett square) X- Y
X- X-X- X-Y
X- X-X- X-Y
F1) 100% of the progeny is expected to be hemophilic (50% X-X- girls + 50% X-Y boys)
- the phenotype of the father ⇒ hemophilic (X-Y)
- the phenotype of the mother ⇒ normal carrier (X+X-) or hemophilic (X-X-)
You can learn more about séx-linked genes at
brainly.com/question/14680914
brainly.com/question/15608757
brainly.com/question/786413
