A male expresses an X linked recessive trait whenever he inherits one recessive allele because he
Correct answer: A. has only one X chromosome
- A. has only one X chromosome
- B. has two Y chromosomes
- C. inactivates the normal allele
- D. lacks the gene altogether
Explanation
With no second X to supply a dominant allele, the single recessive allele has nothing to mask it, a state called hemizygosity. Females need two copies of the same allele to show the trait, which is why these conditions are commoner in men.
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About Mendel's Laws of Inheritance
Mendelian inheritance explains how alleles separate into gametes and assort during reproduction, producing predictable genotype and phenotype ratios. Questions cover dominance, recessiveness, homozygous and heterozygous conditions, the laws of segregation and independent assortment, monohybrid and dihybrid crosses, test crosses and the limits caused by linked genes.
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