Genes present on the X chromosome are known as what?

• A. Autosomal genes
• B. Sex linked genes
• C. Mitochondrial genes
• D. Pseudoautosomal genes

Answer: (B)

Sex-linked genes are the ones located on the X chromosome. These genes sit on the sex chromosomes rather than the autosomes, so their inheritance depends on sex. In humans, males have one X and one Y, so any X-linked allele on their single X is expressed, while females have two Xs and may require two copies for a recessive trait to appear. That distinct pattern is what defines them as sex-linked. (Note: autosomal genes are on non-sex chromosomes, mitochondrial genes are in mitochondria and usually inherited from the mother, and some genes in the X–Y regions are in the pseudoautosomal area that’s shared between the two.)