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प्रश्न
What is back cross?
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उत्तर
The back cross is a cross of an F1 hybrid with any one of the parental genotypes. The back cross is of two types; they are dominant back cross and recessive back cross. It involves the cross between the F1 off spring with either of the two parents.
संबंधित प्रश्न
State Mendel’s law of Independent Assortment.
A homozygous Tall plant (T) bearing red coloured (R) flowers is crossed with a homozygous dwarf plant (t) bearing white flowers (r):
(1) Give the Genotype and Phenotype of the F2 generation.
(2) Give the possible combinations of the gametes that can be obtained from the F2 hybrid.
(3) Give the dihybrid ratio and the phenotype of the offsprings of the F2 generation when two plants of the F1 generation above are crossed.
Test cross involves
In a test cross involving F1 dihybrid flies, more parental type offspring were produced than the recombination type offspring. This indicates
Identify the statementls that is/are NOT the correct reason/s for Mendel's success in his hybridization experiments.
i. Each factor controlled the single trait and is located on separate chromosomes.
ii. In the pea plant, contrasting characters can be easily recognized.
iii. Mendel carefully recorded the number of plants of each type and expressed his results as ratios.
iv. Mendel performed biochemical assays for identifying the position of 'factors' on chromosome.
Two genes ‘A’ and ‘B’ are linked. In a dihybrid cross involving these two genes, the F1 heterozygote is crossed with homozygous recessive parental type (aa bb). What would be the ratio of offspring in the next generation?
What is the difference between genetic drift and change due to natural selection?
How is the sex of a newborn determined in humans?
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.
Sahil performed an experiment to study the inheritance pattern of genes. He crossed tall pea plants (TT) with short pea plants (tt) and obtained all tall plants in F1 generation.
Give a reason why only tall plants are observed in F1 progeny.
