Q21 of 56 Page 1

How do Mendel's experiments show that the

(a) traits may be dominant or recessive,


(b) traits are inherited independently?

Mendel's experiments show that the


(a) According to Mendel’s view of dominant trait, the characteristics or the trait of an organism is determined by the internal factors, these factors always occur in pairs. Out of the two traits, only one of them expresses itself and is known as dominant. The other one which is not expressed is known as Recessive trait.


It can be understood with the help of Mendel’s experiment, when a tall pea plant and a dwarf pea plant is crossed then, the plants appeared in F1 generation are found to be tall which proves that in F1 generation, the dominant was tall character and dwarf were recessive, but in F2 generation, the plants were dwarf. It can be shown as follows:



(b) A cross was made between pure breeding pea plants, one with round and green seeds and the other with wrinkled and yellow seeds. The Phenotype in F1 progeny is yellow and round shape because they are dominant over green and wrinkled seeds, in F1 progeny which can be shown as follows:


diag.png


When F1 progeny was selfed, the following progeny along with the ratio will be obtained:



Therefore, Mendel’s experiment showed that traits are inherited independently.


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