AP BIOLOGY

Detailed explanation-1: -Definition. The X chromosome is one of the two sex chromosomes that are involved in sex determination. Humans and most other mammals have two sex chromosomes (X and Y) that in combination determine the sex of an individual. Females have two X chromosomes in their cells, while males have one X and one Y.

Detailed explanation-2: -X-linked alleles require a specific notation: Xc or X+ where the “+” represents the dominant allele and the lowercase letter the recessive allele. Females will have two X-linked alleles (because females are XX), whereas males will only have one X-linked allele (because males are XY).

Detailed explanation-3: -Traits controlled by genes found only on the X chromosome are said to be sex-linked (see linkage group). Recessive sex-linked traits, such as hemophilia and red–green colour blindness, occur far more frequently in men than in women.

Detailed explanation-4: -Genes on the X chromosome are said to be X-linked. X-linked genes have distinctive inheritance patterns because they are present in different numbers in females (XX) and males (XY).