How do I get these answers? Please explain in detail. Thank you! 15. (12 Points)

Question

How do I get these answers? Please explain in detail. Thank you!

15. (12 Points) Pollen (male gametes) from a plant with red flowers was used to pollinate ovules (female gametes) of a plant with white flowers. All F1 plants had red flowers. When F1 plants were backcrossed to the parental white flower plant generate F2 generation, you observed 1 red: 1 white ratio. In addition, an RFLP (restriction fragment length polymorphism) pattern for the parents, F1, and ten F2 individuals with white flowers is shown below arents Ten F2 plants with white flowers red white F1 9 kb a. Is this RFLP linked to the gene that determines flower color? Briefly explain your answer. (4 points) Yes, because RFLP ratio is not 1:1 b. If they are linked, what is the map distance between them? If they are not linked, check the box below and provide a brief explanation. Show your work and circle your answer. (4 points) 2/10-20% c. If there are any abnormalities in the RFLP result, please briefly explain. (4 points) -The last F2 plant didn't receive a chromosome from the white flower parent. -Non-disjunction happened in the white flower plant (during either meiosis I or meiosis II)

Explanation / Answer

Let us take red color allele to be the dominant allele which is coded by "R" and recessive allele be "r" that codes for white color. So the genotype of F1 flowers with red color flower will be "Rr" heterozygous type. The cross between F1 flower with "Rr" genotype and recessive homozygous parent with genotpe "rr" to give progeny in the ratio of 1:1 having red color and white color flower with genotypes "Rr" and "rr" respectively. a) The RFLP stands for Restriction fragment length polymorphism that depends on fragmentation of DNA molecules by cleaving them with restriction enzymes. Since F1 plant and all the ten F2 progenies shows all a similar pattern of fragments in due respect to their respective allele after the digestion of DNA molecule with restriction enzymes. Thus this gene is linked to RFLP.    b) The two genes are linked to each other i.e. they are present on the same chromosome with a distance of 20 map units between them.

C) The last F2 progeny donot show any allele which is received from the white parent due to non-disjuction of chromosomes. Non-disjunction of chromosomes basically refers to unequal division of chromosome during gamete formation. This unequal distribution of chromosomes may occur at either at meiosis I stage or meiosis II stage. This may result in an extra copy of allele in one gamete and loss of a chromosome or a copy of allele from another gamete. As a result of which the last F2 progeny donot exhibit any allele which is inherited fron white parent plant.

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