Question

write a note on pleitropy​

Answer 1

Answer:

Pleiotropy occurs when one gene influences two or more seemingly unrelated phenotypic traits. Therefore, a mutation in a pleiotropic gene may have an effect on several traits simultaneously due to the gene coding for a product used by a myriad of cells or different targets that have the same signaling function.

Explanation:

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Answer 2

ANSWER:-)

• When a single gene controls two (or more) different traits it is called pleiotropic gene and the phenomenon is called pleiotropy or pleiotropism.

• The phenotypic ratio is 1:2 instead of 3:1 because of the death of recessive homozygote. The disease, sickle-cell anaemia, is caused by a gene Hb^s.

• Normal or healthy gene HbA is dominant. They carriers (heterozygotes Hb^a/Hb^s) show signs of mild anaemia as their RBCs become sickle shaped i.e. half-moon-shaped only under abnormally low 02 concentration.

• The homozygotes with recessive gene Hb^s die of fatal anaemia.

• Thus, the gene for sickle-cell anaemia is lethal in homozygous condition and produces sickle cell trait in the heterozygous carrier. Two different expressions are produced by a single gene.