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1. Describe the steps or procedure ofMendel's experiments with suitableexample.

Answer»

Selection of parents:Mendel selected true breeding pea plants with contrasting characteristics for his experiment. True breeding plant is the one that produces an offspring with the same characteristics on self-pollination. For example, a tall plant is said to be true breeding when all its progeny formed after self-pollination are tall.

Production of F1plants:F1generation is the first filial generation. It is formed after crossing the desirable parents. For example, Mendel crossed a pure tall pea plant with a pure dwarf pea plant. All F1plants were found to be tall.

Results of self-pollination of F1plants:Mendel found that on self-pollination of F1plants, the progenies obtained in F2generations were not all tall plants. Instead, one-fourth of F2plants were found to be short.

Mendel’s explanation for the reappearance of the short trait:

From this experiment, Mendel concluded that F1tall pSelection of parents: Mendel selected true breeding pea plants with contrasting characteristics for his experiment. True breeding plant is the one that produces an offspring with the same characteristics on self-pollination. For example, a tall plant is said to be true breeding when all its progeny formed after self-pollination are tall.

Production of F 1 plants: F1 generation is the first filial generation. It is formed after crossing the desirable parents. For example, Mendel crossed a pure tall pea plant with a pure dwarf pea plant. All F1 plants were found to be tall.

Results of self-pollination of F 1 plants: Mendel found that on self-pollination of F1 plants, the progenies obtained in F2 generations were not all tall plants. Instead, one-fourth of F2 plants were found to be short.

Mendel’s explanation for the reappearance of the short trait:

From this experiment, Mendel concluded that F1 tall plants were not true breeding. They were carrying both short and tall height traits. They appeared tall, because tall trait was dominant over short trait.

Dominant trait: It is a trait or characteristic, which is able to express itself over another contrasting trait. For example, tall plants are dominant over short plants.

Recessive trait: It is a trait which is unable to express its effect in the presence of the dominant trait.

Mendel represented the dominant trait as upper case T (i.e. T for tallness), and the recessive trait as lower case t (i.e. t for shortness). These traits are actually the genes present in the chromosomes of a cell. plants were not true breeding. They were carrying both short and tall height traits. They appeared tall, because tall trait was dominant over short trait.

Dominant trait:It is a trait or characteristic, which is able to express itself over another contrasting trait. For example, tall plants are dominant over short plants.

Recessive trait:It is a trait which is unable to express its effect in the presence of the dominant trait.

Mendel represented the dominant trait as upper caseT(i.e. T for tallness), and the recessive trait as lower caset(i.e. t for shortness). These traits are actually the genes present in the chromosomes of a cell.



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