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प्रश्न
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उत्तर
In a dihybrid cross , two pairs of alleles or contrasting characters are considered in parents.
For example, cotyledon colour and seed shape of pea are used as two pairs of alleles.
Suppose, among the two parents, one was true breeding dominant i.e. yellow coloured cotyledons and round seeds, YYRR and the other was a true breeding recessive i.e. green coloured cotyledons and wrinkled seeds, yyrr. On crossing the two parents, F1 generation so obtained had all yellow and round seeds.
On self pollinating, the hybrids - YyRr produced four types of seeds in F2 generation:
(i) Yellow cotyledons and round seeds (YYRR)
(ii) Yellow cotyledons and wrinkled seeds (YYrr)
(iii) Green cotyledons and round seeds (yyRR)
(iv) Green cotyledons and wrinkled seeds (yyrr)
Thus the phenotypic ratio of a dihybrid cross is 9:3:3:1.
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संबंधित प्रश्न
Which Mendelian idea is depicted by a cross in which the F1 generation resembles both the parents
Define Genetics.
In a testcross involving F1 dihybrid flies, more parental-type offspring were produced than the recombinant-type offspring. This indicates ______.
A normal green male maize is crossed with albino female. The progeny is albino because ______.
Mendel’s Law of independent assortment holds good for genes situated on the ______.
Assertion: When the two genes in a dihybrid cross are situated on the same chromosome, the proportion of parental gene combinations is much higher than the nonparental type.
Reason: Higher parental gene combinations can be attributed to crossing over between two genes.
From the list given below, select the character which can be acquired but not inherited
Do genetic combination of mothers play a significant role in determining the sex of a new born?
Two pea plants - one with round yellow seeds (RRYY) and another with wrinkled green (rryy) seeds produce F1 progeny that have round, yellow (RrYy) seeds.
When F1 plants are self-pollinated, which new combination of characters is expected in F2 progeny? How many seeds with these new combinations of characters will be produced when a total 160 seeds are produced in F2 generation? Explain with reason.
Mendel's law of independent assortment is based on F2 ratio of:
