Location of Sex-Influenced Genes
Genes of sex-influenced traits are present on:
- Sex-chromosomes
- Autosomes — Correct Answer
- Both
- None
Explanation:
Correct Answer: Autosomes
Genes controlling sex-influenced traits are located on autosomes. However, the expression of dominance vs. recessiveness of these alleles is modified by the hormonal environment (sex hormones) of the individual — hence different expression in males vs. females.
Sex-Influenced Traits — Key Features
- Genes on autosomes (not sex chromosomes)
- Expressed in both sexes, but the dominance relationship changes between sexes
- Classic example: Horn condition in Dorset sheep — Horned allele (Hh) is dominant in males (→ horned) but recessive in females (→ polled)
- Another example: Baldness in human — Baldness allele is dominant in males but recessive in females
Comparison of Three Trait Types
| Type | Gene on | Expressed in |
|---|---|---|
| Sex-limited | Autosome | Only one sex |
| Sex-influenced | Autosome | Both sexes (differently) |
| Sex-linked | Sex chromosomes | Both sexes (pattern differs) |
📚 About this Topic — Animal Genetics & Breeding
This multiple choice question is from Animal Genetics & Breeding, Animal Refresher. It has 4 options with a detailed explanation of the correct answer. Practice more MCQs from Animal Genetics & Breeding to strengthen your preparation.
