Title: Material%20from%20Thursday%20September%2019th%20handout%20covered%20on%20Tuesday%20September%2024th
1Material from Thursday September 19th handout
covered on Tuesday September 24th
2Human Pedigrees Polymorphic Traits
3Human Pedigrees X-linked Dominant
4Categories of inheritance
- Autosomal recessive
- e.g., PKU, Tay-Sachs, albinism
- Autosomal dominant
- e.g., Huntington disease
- X-linked recessive
- e.g., color-blindness, hemophilia, DMD
- X-linked dominant
- e.g., hypophosphatemia
- Y-linked
- Organelle
5Calculating probabilities
Aa
Aa
AA
AA
aa
aa
What is the probability that the offspring in
question will have the trait?
6Inheritance of Organelle Genes and
Organelle-linked Traits
In humans
2 rRNA 22 tRNA 13 proteins
7Inheritance of Traits due to Mitochondrial DNA
Mutations
Maternal Inheritance - Affected females pass
trait to all - Affected males never pass on the
trait
8Material from Thursday September 24ths handout
covered Thursday September 24th
9(No Transcript)
10(No Transcript)
11(No Transcript)
12Dihybrid Test Cross
13Dihybrid Self Cross
14Crossing Over creates recombinant progeny for
genes on the same chromosome
15Cis trans crossing-over
cis
trans
meiotic crossing-over
AB/ab ? aB/Ab
Ab/aB ? AB/ab
- Drawing shows only chromatids engaged in
crossing-over - Effect is to switch between cis and trans
16(No Transcript)
17Consequences of crossing-over
- Genetic Analyses
- Frequency of recombinant gametes is 0-50,
depending on frequency of meiocytes with
crossing-over (for syntenic genes) - Results in deviation from 1111 in testcrosses
- parental combination is most frequent
- recombinant combination is rarest
- Allows drawing of linkage maps based on
recombination frequencies (RF) - Chromosome Segregation
- At least one CO per chromosome arm (in humans,
usually only one CO per arm) - Required for equal segregation of homologs during
meiosis I
18HW/Study Problemstopic 4 material covered
through todays lecture
- Solved problems 1,2
- Basic problems 1,2,3,4,5,6,17,18,19,26,