Chromosomal Chromosomal Inheritance and Inheritance and
Human Sex Human Sex DeterminationDetermination
Chromosomes!Chromosomes!
Is this what Mendel would Is this what Mendel would expect?expect?
Is this Is this what what
Mendel Mendel would would
expect?expect?
If a color blind man has a child with If a color blind man has a child with a “wild-type” woman, what are the a “wild-type” woman, what are the chances that this chances that this daughterdaughter of theirs of theirs will be colorblind?will be colorblind?
What are the chances that their What are the chances that their sonson will be colorblind?will be colorblind?
Can females be colorblind? What Can females be colorblind? What would the genotype of the parents would the genotype of the parents have to be?have to be?
Practice Question: Practice Question: Chromosomal InheritanceChromosomal Inheritance
Human Sex Human Sex DeterminationDetermination
Textbook Story:Textbook Story:
XX = FemaleXX = Female
XY = MaleXY = Male
With a few With a few exceptions….exceptions….
OccasionallOccasionally, y,
chromosomchromosomes fail to es fail to
sort sort correctly correctly resulting resulting
in in aneuploidy aneuploidy (unusual (unusual
numbers of numbers of chromosomchromosom
es)es)
XXY = Klinefelter Syndrome- phenotypically male with normal intelligence, sterile
XO = Turner syndrome- phenotypically female, sterile, usually normal intelligence
XYY = no general traits (tall)
XXX = healthy, “normal”
Aneuploidy can also occur with Sex Chromosomes
The The SRY SRY GeneGene
Hormonal Signaling is Hormonal Signaling is ComplexComplex
Hormone Production is Hormone Production is ComplexComplex