Biology, asked by snehavinod34, 1 year ago

Plz someone quickly make a dihybrid cross of first two generations.

Answers

Answered by Devbansal
3
Dihybrid cross is a cross between two different lines (varieties, strains) that differ in two observed traits. In the Mendelian sense, between the alleles of both these loci there is a relationship of complete dominance - recessive. In the example pictured to the right, RRYY/rryy parents result in F1 offspring that are heterozygous for both R and Y (RrYy).[1]

In the name "Dihybrid cross", the "di" indicates that there are two traits involved (e.g. R and Y), the "hybrid" means that each trait has two different alleles (e.g. R and r, or Y and y), and "cross" means that there are two individuals (usually a mother and father) who are combining or "crossing" their genetic information.

The Dihybrid cross is easy to visualize using a Punnett square of dimensions 4 x 4.

The rules of meiosis, as they apply to the dihybrid, are codified in Mendel's first law and Mendel's second law, which are also called the Law of Segregation and the Law of Independent Assortment, respectively.

For genes on separate chromosomes, each allele pair showed independent segregation. If the first filial generation (F1 generation) produces four identical offspring, the second filial generation, which occurs by crossing the members of the first filial generation, shows a phenotypic (appearance) ratio of 9:3:3:1, where:

the 9 represents the proportion of individuals displaying both dominant traitsthe first 3 represents the individuals displaying the first dominant trait and the second recessive traitthe second 3 represents those displaying the first recessive trait and second dominant traitthe 1 represents the homozygous, displaying both recessive traits.
Answered by Anonymous
3
Heya..
Here is your required answer:-

> Dihybrid Cross :- The cross which occurs between the parents showing two alternate forms of two character.

> A principle which is explained by dihybrid cross is 'law of independent assortment'.The character of dihybrid cross done by Mendel was the cross between a homozygous pea plant bearing round and yellow seed( RRYY) and homozygous wrinkled green seeded pea plant (rryy), In F1 generation hybrid plant with yellow seeds were produced which on self pollination produced four type of plant in the ratio of 9:3:3:1 (9 round yellow, 3 round green, three wrinkled yellow and one wrinkled green ) thus., Mendel formulated the principle of independent assortment which can be defined as the inheritance of two or more pair of pair of contrasting traits in such a way that one pair of contrasting traits is independent of the Other pair of contrasting trait.

> cross showing monhybrid cross:-


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