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Mendel’s Contribution(s)?. Mendel’s First Postulate. Unit Factors in Pairs Genetic characteristics are controlled by unit factors that exist in pairs in individual organisms, each individual receives one unit factor from each parent,
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Mendel’s First Postulate Unit Factors in Pairs • Genetic characteristics are controlled by unit factors that exist in pairs in individual organisms, • each individual receives one unit factor from each parent, • in a monohybrid cross, three combinations of unit factors are possible,
Mendel’s Second Postulate Dominant/Recessive • When two unlike unit factors are present in a single individual, one unit factor is dominant to the other, which is said to be recessive.
Mendel’s Third Postulate Segregation • During the processes of heredity, the paired unit factors separate so that the offspring receives one unit factor from each parent, • The unit factors segregate to offspring randomly.
Mendel’s Forth Postulate Independent Assortment • How do two traits segregate in the offspring of an individual that is heterozygous for both traits?
Forked-Line MethodHaplo/Diplo and complementation Both recessive: aaDD x Ad female: AaDd, male aD Both Dominant: aaDD x Ad female: AaDd, male aD One dominant*: aadd x AD female: AaDd, male ad or… AADD x ad female: AaDd, male AD * need to define which is dominant!
1/2 x 1/2 = 1/4 AD ½ D ½ d 1/2 x 1/2 = 1/4 Ad 1/2 A 1/2 D 1/2 x 1/2 = 1/4 aD ½ d 1/2 x 1/2 = 1/4 ad 1/2 a Forked-Line MethodHaplo/DiploAaDd
1/2 x 1/2 = 1/4 AD ½ D ½ d 1/2 x 1/2 = 1/4 Ad 1/2 A 1/2 D 1/2 x 1/2 = 1/4 aD ½ d 1/2 x 1/2 = 1/4 ad 1/2 a Forked-Line MethodHaplo/DiploAaDd x AD* (*male genotype could be ad, aD, Ad) 1 AD = ¼ ADAD 1 AD = ¼ AdAD 1 AD = ¼ aDAD 1 AD = ¼ adAD
C. elegans Nomenclature Tower of Babel