Presentation on theme: "D. Multiple Alleles – Instead of having two forms of an allele, there are more than two for one gene. i. The best example for humans is blood. There 3."— Presentation transcript:
1 d. Multiple Alleles – Instead of having two forms of an allele, there are more than two for one gene.i. The best example for humans is blood. There 3 alleles for blood types in humans: A, B and O. A and B are co dominant while O is recessive.
2 Multiple Alleles – Blood Type Type A genotypes could be: IAIA or IAi.Type B genotypes could be: IBIB or IBi.Type AB genotype is: IAIBType O genotype is: ii
3 PracticeA man who is heterozygous for type A blood marries a woman who is heterozygous for type B blood. Find the possible outcomes
4 e. Sex linked traitsi. Autonomies – there are 44 (22, pairs) of non sex chromosomes.ii. Sex Chromosomes – the 23rd pair of chromosomes are the sex chromosomes.The genotype for females is XX; the genotype for males is XY.
5 e. Sex linked traitsiii. Sex linked traits – Are genes located on the X chromosome. There is almost no information located on the Y chromosome.Since males have only one X chromosome they show whatever allele is on the X chromosome, regardless of whether it is dominant or recessive.
6 e. Sex linked traitsiii. This is the only time that a single recessive allele is expressed.Two examples of sex-linked traits in humans are red/green colorblindness and hemophillia. (A recessive sex linked trait that keeps your blood from clotting.)
11 Sex linked traits - Colorblindness If normal vision (N) is dominant to colorblindness (n) give the genotypes for each of the following:A female carrier: XNXnA homozygous dominant female: XNXNColorblind male: XnYColorblind female: XnXnA male with normal vision: XNY
12 Sex linked traits Who does the male get the X chromosome from? Mother Who does a male inherit recessive sex linked traits from? MotherWho are colorblind more often, men or women? Men; no information on Y to mask the recessive trait on X.
13 PracticeA female carrier has a child with a male with normal vision. What are the chances of colorblindness occuring in: Son? Daughter?
14 PracticeA colorblind male has a child with a normal female. Fill out the cross.