Q. 24.0( 5 Votes )
How do Mendel's experiments show that the (a) traits may be dominant or recessive (b) traits are inherited independently?
a) Traits are dominant and recessive.
• Mendel performed an experiment on the pea plant. He crossed the tall pea plant with allele (TT) with the small pea plant (tt). As a result of this crossing, the progeny of the F1 generation were all tall.
• By this, he showed that the traits maybe dominant or recessive.
• The traits which were expressed in the progeny in both heterozygous (Tt) as well as homozygous (TT) condition are the dominant traits.
• Whereas the traits which are only expressed in homozygous condition (tt) are the recessive trait.
The cross to show recessive and dominant traits is given below:
b) Traits are inherited independently.
• Mendel showed that traits are inherited independently by performing a cross between two different traits using both dominant and recessive characters on a dihybrid cross.
• A dihybrid cross is one in which two different traits are crossed and studied.
• He crossed two different traits and the result came that neither of the characters is dependent on the other for sorting.
• He crossed a plant with round shape (dominant) and green color (recessive) peas with wrinkled shape (recessive) and yellow color (dominant) peas.
• In the cross, it was observed that the segregation (separation) of traits was not dependent on each other. The plant of the F2 generation has plants with any traits out of the two.
• It was round with green, round with yellow, wrinkled with green and wrinkled with yellow peas.
• It doesn’t matter, that, if one trait was dominant, then other has to be dominant too. It can be either dominant or recessive.
• This is also known as Independent assortmentc
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