Download Variations of Mendel`s Law Notes Incomplete

Variations of Mendel’s Law Notes
Incomplete Dominance:
NOT Blending Hypothesis because …
In northeast Minnesota there is a creature know as a wildcat. It
comes in three colors, blue, red, and purple. This trait is
controlled by a single locus gene with incomplete dominance.
A homozygous (BB) individual is blue, a homozygous (bb)
individual is red, and a heterozygous (Bb) individual is purple.
What would be the genotypes and phenotypes of the offspring
if a blue wildcat were crossed with a red one?
Multiple Alleles: .
Ex. Human Blood Type
- Alleles
Co-dominance:
Ex. Blood Type __________
For each of the following crosses tell us the proportions of genotypes and phenotypes: (show your work in
a Punnett Square)
Cross a homozygous type A with a heterozygous type B.
Cross a type AB person with a heterozygous type A.
Cross a type 0 person with a homozygous type B
Sickle Cell Allele
Pleiotropy:
Sometimes may have a
________________ amount of
_____________________
Resistant to _______________________
Sickle Cell Heterozygotes
Usually ___________________
Explain in your own words why…
Polygenic inheritance
Additive effects of ________________________
on a _____________phenotypic characteristic.
This is the opposite of ________________
in which a single gene affects several
characteristics.
Chromosome Theory of Inheritance
Genes occupy specific _____________ (positions) on
chromosomes and it is the chromosomes that undergo
_______________ and
_________________ assortment
during meiosis.
As a result…
Linked Genes
•
Linked genes are ones that are located __________________________
on the ______________________________________.
•
Linked genes do not follow the rules of _________________________
because they are found on the same chromosome.
•
Only individual chromosome ______________________ not
__________________________________
Crossing Over
___________________________ gametes result from crossing over
This results in a new ________________________________ (recombinant phenotype)
Thomas Hunt Morgan Experiment
Studied crossing over in ______________________ (Drosophila melanogaster)
G=
(dominant)
g=
(recessive)
L=
(dominant)
l=
If these traits were not linked then the cross should result in a
_____________________
He ended up with ___________________ recombinants
Not a 1:1:1:1 frequency
Recombination frequency:
He assumed that genes had to be located ________________
on a chromosome for the frequency of recombination to be
__________.
They can use the recombination frequency to
determine…
Chromosomes determine sex
•
•
•
Sex-Linked Genes Pattern of Inheritance
•
•
Sex-linked Gene:
Sex-linked disorders are more common in __________ because…
•
A recessive trait would show more often in males because it would only need one
________________to show.
•
A couple are both phenotypically normal, but their son suffers from hemophilia, a sex-linked
recessive disorder. What fraction of their children are likely to suffer from hemophilia? What
fraction are likely to be carriers?
•
Heather was not able to see the numeral 7 in Figure 9.24Aand was surprised to discover she
suffered from red-green color blindness. She told her biology teacher, who said, “Your father is
color-blind too, right?” Show how the teacher would know this? Why did the professor not say the
same thing to the color-blind males in the class?