Sex-linked traits, Blood Types

Sex-linked traits X Y X XX XY X XX XY Male Sex Chromosomes determined at the moment of : Conception (fertilization) Female Genotype: XX Sex chromosome that a female can give: X Male Genotype: XY Sex chromosome that a male can give: X or Y Punnet Square showing the cross of possible chromosomes between a male and female. X Y Who determines the sex of the child? Probability of Male: 50% X XX XY Probability of Female: 50% X XX XY Male

Sex-linked Inheritance A sex-linked gene is a gene located on the X chromosome. No gene is written on the Y. Eye color in Drosophilia is sex-linked. The gene for red eyes is dominant over the gene for white R = Red r=White Genotype for a homozygous red-eyed female XRXR Genotype for a heterozygous red-eyed female XRXr Genotype for a white-eyed female is XrXr Genotype for a red-eyed male is XRY Genotype for a white-eyed male is XrY

Phen: Red-eyed Female & Red-eyed Male Y XRY XRY 6. If a homozygous red-eyed female Drosophilia mated with a white-eyed male, what are the expected genotypic and phenotypic ratios in the F1 generation? F2? P: XRXR x XrY F1: F1 Gen: XRXr & XRY XR XR Xr XRXr XRXr Phen: Red-eyed Female & Red-eyed Male Y XRY XRY

Gen: XRXR; XRXr; XRY; XrY XR Xr 6. If a homozygous red-eyed female Drosophilia mated with a white-eyed male, what are the expected genotypic and phenotypic ratios in the F1 generation? F2? F1 Gen: XRXr & XRY Phen: Red-eyed Female & Red-eyed Male F2: F2: Gen: XRXR; XRXr; XRY; XrY XR Xr XR XRXR XRXr Phen: Red-Eyed Female Red-Eyed Male; White-eyed Male Y XRY XrY

Blood Types IB i IB IBIB IBi IBi ii i Gen: IBIB; IBi; ii 2. Father: B Possible father genotype: IBIB or IBi 1. P: IBi x IBi IB i Child: AB Child genotype: IAIB IB IBIB IBi IBi ii i Mother must carry the A gene Gen: IAi; IAIA; IAIB Phen: Type A or Type AB Gen: IBIB; IBi; ii Phen: Type B & Type O

Phenotypes: Type A & Type B 3.) List out all the blood types in a punnett square Work backwards from there. IA i IB IAIB IBi Genotypes: IAi & IBi IAi i ii Phenotypes: Type A & Type B

i i IA IAi IAi IBi IBi IB Mr. Poe Type O ii Mrs. Poe Type AB IAIB Mr. Doe Type B IBi or IBIB Mrs. Doe Type B IBi or IBIB Mary Type A IAi or IAIA John Type O ii Mr & Mrs. Poe Children potential i i IA IAi IAi IBi IBi IB Mr & Mrs. Poe can only have have children with type A or B blood. Is John their baby? Was there a mistake? YES!!!!!!!!!!!!!