Download Non-Mendelian Genetics Notes

Non-Mendelian Genetics
Connections:
• Know how to set setup a sex-linked cross, co-dominance cross, and incomplete dominance cross.
• Determine genotypic and phenotypic ratios for a sex-linked cross, co-dominance cross, and incomplete dominance cross.
Review
•
In Mendelian genetics, there are only _________ alleles.
•
One allele is __________________ and one allele is ____________________.
Non-Mendelian Genetics
•
Most genetics do not follow these rules.
•
Today we will talk about _______________ exceptions
o _________________________________
o _________________________________
o _________________________________
Sex-Linked Traits
•
Females possess the sex chromosomes _______. •
Males possess the sex chromosomes ________.
o Most sex-linked genetic disorders are found on the _____
chromosome.
o It is the ________________ of the two.
•
Since males only have _________ X chromosome they are _____________ likely to have sex-linked
disorders than females.
o Most sex-linked disorders are _____________________.
o Males only get _______ X chromosomes, so they only need ________ allele to show the
disorder.
o Females need ___________ alleles to have trait.
Colorblindness
•
The genes for colorblindness are found on the _____ chromosome.
o It is more common in males, because they only receive _________ X chromosome.

Therefore, if they get the “colorblind” ____________ on their
one X they will be ________________________.
o For females to have colorblindness, __________ X chromosomes must
have the “colorblind” allele. Sex-linked Punnett Square
•
Sex-linked traits are usually written as _________
•
Let’s look at a cross between a ________________ female and a ________________________ male.
o Carrier means they are _________________________, but do _______ show the trait
(phenotype)
Sex-linked Punnett Square
Chance of getting a female = ____________
Chance of getting a male = _____________
Chance of getting a normal female = ________
Chance of getting a colorblind male = ________
Chance of getting a carrier female = ________
Chance of getting a colorblind female = ________
Chance of getting a normal male = ________
Co-dominance
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When the phenotype of a heterozygous individual shows ________
alleles.
•
Example – Blood Type
o Individuals who are ______ blood type have some blood cells
with ____ proteins and some blood cells with _____ proteins.
o So, ________ phenotypes are present. Co-dominance Punnett Square
•
Let’s cross horses that exhibit co-dominance.
o A ___________ horse is crossed with a ____________ horse. o Brown = ____
o White = _____
Co-dominance Punnett Square
a) Since _____________ brown or white is _______________ over
one another horses with ________ alleles will show _______ traits.
b) This pairing will give you _______ brown and white spotted offspring.
Incomplete Dominance
•
When the phenotype of a heterozygous individual is a __________________ of both alleles.
o In this situation, _______ allele is ________________ over another.
o _____________ phenotypes indicates incomplete dominant genetics.
Incomplete Dominance Punnett Square
•
Let’s cross _______________ that exhibit incomplete dominance.
o If a ______________ (_____) flowered individual is crossed with a homozygous _______
flowered individual (_____).
Incomplete Dominance Punnett Square
Since ______________ red or white is dominant over one another
the flowers will show a _________________ of the two.
This pairing will give you _________ pink flowers.