SexLinked Traits By Lauren Beggs Agenda 2262013 n

Sex-Linked Traits By: Lauren Beggs

Agenda 2/26/2013 n Turn in 7. 2 KT’s and questions 1 -6 n n n 7. 2 KT’s and questions 1 -6 Incomplete Dominance Wkst HW: Read 7. 1, KT’s, and questions 1 -5

Bellringer 2/26/2013 Shh! Don’t tell your answer. n Can you see a number in this picture? If so… what number do you see?

Estimated: n 1/10 Caucasian males are colorblind n 1/20 Caucasian females are colorblind. Why is color-blindness more prevalent in males than in females?

Sex-Linked Traits n n n Mendel only studied traits on autosomes. Autosomes: only contain genes unrelated to the sexual characteristics of an organism Sex Chromosomes: contain genes that code for the sexual characteristics of an organism

Sex-Linked Traits n Sex-Chromosomes n n Females = XX Males = XY female There are thousands more genes on the X chromosome than the Y chromosome. Who determines the sex of the child? Mom or dad?

Sex-Linked Traits Mom Dad Diploid Parent Cell XY XX X X Haploid Gametes X Y

Sex-Linked Traits #1 Egg Sperm X Offspring: #2 Egg Offspring: X XX Sex of the child? Y X XY Sperm Sex of the child?

n Sex-Linked Genes: Genes located on the sex chromosomes.

Sex-Linked Traits n n n Calico is coat fur color found in cats, which is caused by a SEX-LINKED, CODOMINANT allele. B = Black R = o. Range BR = calico cat

Sex-Linked Traits Female genotypes, phenotypes? n XBXB _______ n XBXR _______ n XRXR _______ Male genotypes, phenotypes? n XBY _______ calico cat n XRY _______

Sex-Linked Traits Female genotypes, phenotypes? n XBXB -- Black n XBXR -- Calico n XRXR -- Orange Male genotypes, phenotypes? n XBY -- Black n XRY -- Orange calico cat

Sex-Linked Traits A black male cat is crossed with an orange female cat. x Predict the phenotypes and genotypes of the offspring for both males AND females.

Sex-Linked Traits Male: XBY x Female: XRXR Predict the phenotypes and genotypes of the offspring for both males AND females.

Sex-Linked Traits Male: XBY XR x XB Y XR XB XR Y Female: XRXR 100% Females = calico 100% Males = orange XR XR XB XR Y

Sex-Linked Traits An orange male cat is crossed with an calico female cat. x Predict the phenotypes and genotypes of the offspring for both males AND females.

Sex-Linked Traits Male: XRY x Female: XRXB Predict the phenotypes and genotypes of the offspring for both males AND females.

Sex-Linked Traits Male: XRY x XR Y XR XR Y XB XR XB XB Y Female: XRXB 50% Females = calico 50% Females = orange 50% Males = black

…Food for Thought n If almost 10% of the population can’t differentiate between red & green…than why is the “stop” and “go” on a traffic light red and green? !