Which of the following trait shows transmission from carrier female to male progeny ?

Options

A. Autosomal domainant
B. X- linked recessive
C. Y - linked recessive
D. X - linked dominant

Answer

To determine which trait shows transmission from a carrier female to male progeny, we need to analyze the inheritance patterns of different types of genetic traits. Here's a step-by-step breakdown of the solution:

### Step 1: Understand the Types of Genetic Traits
- Genetic traits can be classified into various categories, including autosomal traits and sex-linked traits (X-linked and Y-linked).
- X-linked traits are those that are located on the X chromosome, while Y-linked traits are located on the Y chromosome.

**Hint:** Remember that traits can be autosomal (not linked to sex chromosomes) or sex-linked (associated with X or Y chromosomes).

### Step 2: Focus on X-linked Traits
- Among sex-linked traits, X-linked traits are particularly important when considering inheritance from a mother to her son.
- Males have one X chromosome (inherited from their mother) and one Y chromosome (inherited from their father), while females have two X chromosomes.

**Hint:** Consider how the X and Y chromosomes are inherited from parents to offspring.

### Step 3: Identify Carrier Females
- A carrier female has one normal X chromosome and one defective X chromosome (for example, carrying a gene for hemophilia).
- Since females have two X chromosomes, the presence of one normal X chromosome can mask the effect of the defective gene, meaning the female is a carrier but does not express the trait.

**Hint:** A carrier female can pass on either of her X chromosomes to her children.

### Step 4: Transmission to Male Progeny
- When a carrier female has a son, she can pass on either her normal X chromosome or her defective X chromosome.
- If the son inherits the defective X chromosome, he will express the trait associated with that gene (e.g., hemophilia or color blindness) because males do not have a second X chromosome to mask the effect of the recessive gene.

**Hint:** Think about what happens when a son receives an X chromosome from his mother.

### Step 5: Conclusion
- The trait that shows transmission from a carrier female to male progeny is an X-linked recessive trait.
- Common examples of such traits include hemophilia and color blindness, which are more frequently observed in males than in females.

**Final Answer:** X-linked recessive traits show transmission from a carrier female to male progeny.