Biology as Poetry: Genetics

Bacteriophage Ecology Group

Sex Chromosome

Gender-determining genetic complex (double helix) employed by many animals.

Mammals employ the X and Y sex chromosomes with females XX and males XY. Birds and various other animals by contrast employ what is known as the ZW sex determination system, where females are ZW and males are ZZ. In other animals the presence of two sex chromosomes (XX) versus a relative absence (just X or, as typically denoted, X0) determines gender (X0 sex-determination system).

See also sex linked traits and Sex-linked recessive conditions. Contrast sex chromosome with autosome.

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