Question

If a trait passes from father to all his daughters but none of his sons, the trait is:
(A) Autosomal dominat
(B) Autosomal recessive
(C) Sex linked dominant
(D) Sex linked recessive

Answer 1

Hint: The gene pair is dominated by the aberrant gene. In the case of an X-linked dominant disorder, all of the father's daughters will acquire the condition and none of the father's boys will be affected. This is so because daughters always receive an X chromosome from their father.

Complete Step by Step Answer:
A genetic disorder or trait can be transferred from parent to kid via autosomal dominant inheritance. The genetic disorder can be brought on by one copy of a mutant (changed) gene from one parent. A child has a 50% chance of receiving the mutant gene from a parent who carries it. Using autosomal recessive inheritance, a genetic disorder or trait can be passed from parent to offspring. When a child receives one copy of a mutant (changed) gene from each parent, a genetic disease may result. A child with an autosomal recessive disease typically does not have affected parents. Through mutations (changes) in a gene on a single X chromosome, a genetic characteristic or condition can be handed down from parent to kid through X-linked dominant inheritance.

A gene mutation on one of the X chromosomes is all that is required to induce the disorder in females (who have two X chromosomes). Rett syndrome, the X-linked lissencephaly and double-cortex syndrome, and incontinentia pigmenti type 1, which is marked by anomalies of the skin, eyes, teeth, and nervous system, are examples of X-linked dominant illnesses. Genetic disorders connected to mutations in genes on the X chromosome are referred to as having X-linked recessive inheritance. Because he contains just one X chromosome, a male who carries this mutation will be affected. A female who carries a gene mutation in one X chromosome but has a normal gene on the other X chromosome usually has no symptoms.

So, option (C) is correct.

Note: It is obvious that a gene is only present on the Y chromosome if a trait is handed only to a man's sons. Only fathers can pass on holandric genes to their sons. The reason is because whereas human females have XX as the makeup of their sex chromosome, human males have XY as their sex chromosome.