How does epistasis affect proportion of phenotypical form, Biology

Assignment Help:

In the hybridization of 2 genes (4 different alleles, 2 of each pair) how does epistasis affect the proportion of phenotypical forms in the F2 generation?

In the dihybridism without epistasis double heterozygous parental individuals cross and in F2 4 phenotypical forms appear. The amount is 9 double dominant to 3 dominant for the first pair, recessive for the second to 3 recessive for the first pair, dominant for the second to 1 double recessive (9:3:3:1).

Considering so as to the epistatic gene is the second pair and that the recessive genotype of the hypostatic gene means lacking of the characteristic, in the F2 generation of the dominant epistasis the following phenotypical forms would emerge: 13 dominant for the second pair or recessive for the first that is the characteristic does not manifest, 3 dominant for the first pair, recessive for the second That is the characteristic manifests. Phenotypical proportion would be 13:3. In recessive epistasis in F2 the phenotypical forms that would emerge are: 9 double dominant (the characteristic manifests), 7 recessive for the first pair or recessive for the second that is the characteristic does not manifest. hence the phenotypical proportion would be 9:7.

These instances show how epistasis changes phenotypical forms and proportions, from the normal 9:3:3:1 in F2 to 13:3 in the dominant epistasis or to 9:7 in recessive epistasis (note that some forms have even disappeared) and if the recessive genotype of the hypostatic gene is active, not simply meaning that the dominant allele does not manifest, the number of phenotypical forms in F2 changes.

 


Related Discussions:- How does epistasis affect proportion of phenotypical form

Homeopathic cures, If water dousing, homeopathic cures, and so on work for ...

If water dousing, homeopathic cures, and so on work for just me but not for anyone else, it is still science.

What bacterial cell structures are used to carry the genes, What bacterial ...

What bacterial cell structures are used to carry the genes intended for genetic engineering? The cells structures in bacteria which carry genes intended for genetic engineering

Germplasm conservation - plant tissue and organ culture, Germplasm Conserva...

Germplasm Conservation - plant tissue and organ culture Totipotent plant cells and shoot tips can be freeze-preserved in liquid nitrogen (-196? C) for long periods, and wh

What is the difference between red and white blood cells, Q. What is the di...

Q. What is the difference between red and white blood cells? What are leukocytes? White blood cells are the leukocytes and Red blood cells are erythrocytes. Leukocytes are p

What do you mean by astigmatism and presbyopia, Q. What are astigmatism and...

Q. What are astigmatism and presbyopia? Presbyopia is the visual impairment in which there is loss of the cililary muscle strength thus reducing the ability of the crystalline

Similarities between chlorplasts and prokaryotic cells, What are the simila...

What are the similarities between chlorplasts and prokaryotic cells?

Intermediate products of anaerobic respiration, (a) What are the intermedia...

(a) What are the intermediate products of anaerobic respiration in an active muscle? (b) Which of them is associated with oxygen debt? (c) In what way is th

What is neurotransmitters , When the action potential reaches the nerve ter...

When the action potential reaches the nerve terminal it causes the let go of a chemical neurotransmitter by the synaptic vesicles. Mammalian nervous system employs many substances

Chromophore - development of plant, Chromophore - Development of plant ...

Chromophore - Development of plant The chromophore is a tetrapyrrole molecule like chlorophyll, but unlike chlorophyll it is an open tetrapyrrole and contains no metal ion. It

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd