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sex chromosome n.
Either of a pair of chromosomes, usually designated X or Y, that combine to determine the sex and sex-linked characteristics of an individual, with XX resulting in a female and XY in a male.
sex chromosome |
Either of a pair of chromosomes, usually called X and Y, that in combination determine the sex of an individual in many animals and in some plants. In mammals, XX results in a female and XY in a male, while the opposite is true in birds (where the designations ZW for female and ZZ for male are often used). Sex chromosomes carry the genes that control the development of reproductive organs and secondary sex characteristics. In some organisms, sex is determined by environmental influences. See also X-chromosome, Y-chromosome.
Note: As with other pairs of chromosomes, one of the sex chromosomes is contributed by each parent; they are of two types, X and Y. The mother supplies only an X-chromosome, but the father can transmit both the X- and the Y-chromosome. At fertilization, if the father's sperm is also carrying an X-chromosome, the child will be female. If the father's sperm is carrying a Y-chromosome, the child will be male.