Question

(i) A gene can express more than one trait. What gives rise to different expressions?
(ii) When a true breeding pea plant which has yellow seeds is pollinated by a plant that has green seeds, all the F 1 plants have yellow seeds. What might have been the allele for yellow seeds (tell whether it was dominant or recessive / heterozygous or homozygous )?

Answer 1

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(i) Yes, a gene can express more than one trait. Different expressions or the alleles of the same genes rises due due to the inheritation of genes from both parents with different alleles of the same genes. This is y why there is a rise of different expressions.

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(ii) Here, one plant has yellow seeds whereas The other has green seeds.

We know that yellow seeds are dominant gene and green seeds are recessive ones.

Now, with the help of the given information we can write: YY × yy.

All the filial 1 generation plants are known to be with yellow seeds. This is only possible when the parent plants are homozygous. One of them should be with homozygous alleles of yellow seeds and the other should be with homozygous alleles of green seeds.

In the situation all the plants produced in generation 1 will be yellow seeded and will be heterozygous.

So, the answer for this question is: The alleles of yellow seeds are dominant and homozygous.

Extra Information: If we take alleles of the parents heterozygous and yellow seeded, all the plans in generation 1 will not be yellow seeded. One 4th part of the plants will be homozygous yellow seeded, half of them will be heterozygous yellow seeded and one fourth of them will be homozygous green seeded.

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