Transcript X n Y
*Sex influenced traits *The gene is NOT on a sex chromosome, but SEX affects the phenotype *Example-baldnessdominant in males, recessive in women *If ‘B’ represents bald and ‘b’ is hairy then Men must be bb to keep hair Women can be Bb or BB to keep hair *Caused by a gene that is located on a SEX chromosome (X or Y) *Most sex-linked traits are found on the X chromosome *Is the pedigree beside this like MOST sexlinked traits? * *Most are recessive *Examples-hemophilia, red-green colorblindness *Males are more likely to have these because they cannot be carriers *Why? *Males are XY-if their ‘X’ has a bad gene, there is nothing on the ‘Y’ to dominate over it * *N n * XNXN=Normal * XNXn=CARRIER, but IS NOT colorblind * XNY=Normal * XnY=HAS red-green colorblindess * *Carrier mom XNXn *Normal Dad XNY XN Xn XN XN XN X N Xn Y XNY XnY * * *Orange and Black Alleles are on the X chromosome in cats *White is on another chromosome (autosome). *Result-some cells make black fur, some orange * *Polygenic-more than one pair of alleles determines phenotype--eye color *Female genotype? *Male genotype? *What percent of possible offspring are female? *What percent of possible offspring are male? * What is the genotype of a woman who is a carrier of hemophilia? What is the genotype of a man who does not have hemophilia? Will any of their children potentially have hemophilia? What sex will the child have to be? Last vocabulary term of importance. Purebred – Always breeds true to dominant trait. i.e. homozygous dominant individual