Sex Linked Genes

Sex Chromosomes: X and Y Genotypes: XX and XY Some genes are absent from the Y chromosome. Phenotypes: Female and Male

Sex is determined by the combination of X and Y Chromosomes XX x XY Genotypes: XX and XY Phenotypes: Female, Male X XX XX Y XY XY

Carrier - An individual that has one copy of a recessive allele that causes a genetic disease in individuals that are homozygous for this allele. Female Carriers are heterozygous for X-linked recessive disorders. Sex Linkage - Genes associated with the X or Y chromosome. Most are found on the X Chromosome.

XB Xb XB XBXB XBXb Y XBY XbY Color Blindness: Carried on the X chromosome (Xb) Carrier Female XBXb crossed with Normal Male XBY XB Xb Genotypes: XBXB and XBY XBXb and XbY Phenotypes: Normal Female Normal Male Carrier Female Colorblind Male XB XBXB XBXb Y XBY XbY

XB Xb Xb XBXb XbXb Y XBY XbY How can a Female inherit a Sex Linked disorder? Carrier Female XBXb crossed with Colorblind Male XbY XB Xb Genotypes: XBXb and XBY XbXb and XbY Phenotypes: Carrier Female Normal Male Colorblind Female Colorblind Male Xb XBXb XbXb Y XBY XbY

XH Xh XH XHXH XHXh Y XHY XhY Hemophilia: Carried on the X chromosome (Xh) Carrier Female XHXh crossed with Normal Male XHY XH Xh Genotypes: XHXH and XHY XHXh and XhY Phenotypes: Normal Female Normal Male Carrier Female Hemophilia Male XH XHXH XHXh Y XHY XhY