Eggs and sperm, as reproductive cells, each contain only one of the two where are sex chromosomes located chromosomes as a result of having undergone meiosisa form of cell division that produces daughter cells containing only one member of each chromosome pair. Dominant inheritance occurs when where are sex chromosomes located abnormal gene from one parent causes disease even though the matching gene from the other parent is normal. Since only men inherit Y chromosomes, they are the only ones to inherit Y-linked traits. It could also result from exposure, often in utero, to chemicals that disrupt the normal conversion of the allosomes into sex hormones and further into the development of either ambiguous outer genetilia or internal organs. Sex linked diseases are passed down through families through one of the X or Y chromosomes.
Development of the reproductive system. Autosomes are homologous chromosomes i. Pathways, molecular interactions and genetic disorders".
An example of such a genetic mosaic is a calico cat, carrying an allele for orange fur color on one X chromosome and an allele for black fur color on the other X chromosome. Since males carry only one copy of each X-linked gene, they are much more likely to suffer from disease if they inherit a defective gene.
Hermaphrodite Intersex Disorders of sex development Sex reversal. Evolution of sexual reproduction Anisogamy Isogamy Germ cell Meiosis Gametogenesis Spermatogenesis Oogenesis Gamete spermatozoon ovum Fertilization External fertilization Internal fertilization Sexual selection Plant reproduction Fungal reproduction Sexual reproduction in animals Sexual intercourse Copulation Human reproduction. Sexual differentiation humans Development of the reproductive system gonads Mesonephric duct Paramesonephric duct.
An allele is either said to be dominant or recessive. Most of the genes on the condensed X chromosome cannot be expressed. Since only men inherit Y chromosomes, they are the only ones to inherit Y-linked traits.
To equalize the dosage of X chromosome genes between the two sexes, one of the two X chromosomes in each cell of all female mammals is inactivated early in embryonic development by becoming very tightly wound up or condensed. Men and women can get the X-linked ones since both inherit X chromosomes. All eggs therefore contain an X chromosome, but half of sperm will contain an X chromosome and the other half a Y chromosome.