Mendel’s Mendel’s Contribution(s)?Contribution(s)?

Mendel’s First PostulateMendel’s First Postulate

Unit Factors in PairsUnit Factors in Pairs

Genetic characteristics are controlled by unit Genetic characteristics are controlled by unit factors that exist in pairs in individual organisms,factors that exist in pairs in individual organisms,

each individual receives one unit factor from each individual receives one unit factor from each parent,each parent,

in a monohybrid cross, three combinations of in a monohybrid cross, three combinations of unit factors are possible,unit factors are possible,

Mendel’s Second PostulateMendel’s Second Postulate

Dominant/RecessiveDominant/Recessive

When two unlike unit factors are present in a When two unlike unit factors are present in a single individual, one unit factor is dominant to single individual, one unit factor is dominant to the other, which is said to be recessive.the other, which is said to be recessive.

Mendel’s Third PostulateMendel’s Third Postulate

SegregationSegregation

During the processes of heredity, the paired During the processes of heredity, the paired unit factors separate so that the offspring unit factors separate so that the offspring receives one unit factor from each parent,receives one unit factor from each parent,

The unit factors segregate to offspring The unit factors segregate to offspring randomly.randomly.

Mendel’s Forth PostulateMendel’s Forth Postulate

Independent Independent AssortmentAssortment

How do two traits segregate in the offspring of How do two traits segregate in the offspring of an individual that is heterozygous for both an individual that is heterozygous for both traits?traits?

Forked-Line MethodForked-Line MethodHaplo/Diplo and complementationHaplo/Diplo and complementation

1.1. Both recessive:Both recessive: aaDD x Ad aaDD x Ad female: AaDd, male aD female: AaDd, male aD

2.2. Both Dominant:Both Dominant: aaDD x Ad aaDD x Ad female: AaDd, male aD female: AaDd, male aD

3.3. One dominant*:One dominant*: aadd x AD aadd x AD female: AaDd, male ad female: AaDd, male ador…or… AADD x ad AADD x ad female: AaDd, male AD female: AaDd, male AD

* need to define which is dominant!* need to define which is dominant!

Forked-Line MethodForked-Line MethodHaplo/DiploHaplo/Diplo

AaDdAaDd

1/2 A

1/2 a

½ D

½ d

1/2 D

½ d

1/2 x 1/2 = 1/4 AD

1/2 x 1/2 = 1/4 Ad

1/2 x 1/2 = 1/4 aD

1/2 x 1/2 = 1/4 ad

Forked-Line MethodForked-Line MethodHaplo/DiploHaplo/Diplo

AaDd x AD* (*male genotype could be ad, aD, AaDd x AD* (*male genotype could be ad, aD, Ad)Ad)

1/2 A

1/2 a

½ D

½ d

1/2 D

½ d

1/2 x 1/2 = 1/4 AD

1/2 x 1/2 = 1/4 Ad

1/2 x 1/2 = 1/4 aD

1/2 x 1/2 = 1/4 ad

1 AD = ¼ ADAD

1 AD = ¼ AdAD

1 AD = ¼ aDAD

1 AD = ¼ adAD

LabLab Life CyclesLife Cycles

Wasp Development Wasp Development TimelinesTimelines

1818oo, 28, 28o o CC

C. elegans C. elegans NomenclatureNomenclature

Tower of Babel