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प्रश्न
Very Short Answer Question.
What is crossing over?
उत्तर
- Crossing over is a process that produces new combinations (recombinations) of genes by interchanging and exchanging of corresponding segments between non-sister chromatids of homologous chromosomes.
- It occurs during pachytene of prophase I of meiosis.
- The mechanism of crossing over consists of four sequential steps such as synapsis, tetrad formation, crossing over, and terminalisation.
- The phenomenon of crossing over is universal and it is necessary for the natural selection because it increases the chances of variation.
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संबंधित प्रश्न
Which of the following is NOT an example of connecting link?
- Archaeopteryx
- fchthyostegia
- Seymouria
- Biston betularia
From the following disorders identify the ODD one.
Which of the following statement/s are INCORRECT with respect to crossing over?
i. Crossing over produces recombinations of genes by interchanging and exchanging corresponding segments between nonsister chromatids of homologous chromosomes.
ii. Crossing over occurs during zygotene of prophase I of meiosis.
The phenomenon of ____________ is universal and it is necessary for the natural selection, because it increases the chances of variation.
Two dominant non-allelic genes are 50 map units apart. The linkage is ______.
A fruit fly heterozygous for sex-linked genes, is mated with normal female fruit fly. Male specific chromosome will enter egg cell in the proportion ______.
To determine the genotype of a tall plant of F2 generation, Mendel crossed this plant with a dwarf plant. This cross represents a ______.
Which of the following is correct for the condition when plant YyRr is back crossed with the double recessive parent?
Genes located very close to one another on same chromosome tend to be transmitted together and are called as ______.
From a cross AABb x aaBb, the genotypes AaBB : AaBb : Aabb will be obtained in the ratio ______.
