In genetic screening, detecting differences between individuals often relies on
ID: 203664 • Letter: I
Question
In genetic screening, detecting differences between individuals often relies on differences in repeat numbers of short DNA sequences. What is the process by which these differences in repeat numbers between individuals arise?
A. Restriction enzymes cut and ligate them
B. Some offspring obtain different numbers of chromosomes
C. Recombination events lead to unequal exchange of genetic material
D. These repeat sequences are transcribed more frequently
E. Single nucleotide polymorphisms cause them
PLEASE ALSO EXPLAIN WHY
Explanation / Answer
lets see each possibilites stepwise,
individuals are different from each other due to the different numbers of DNA repeats present in our genome. these are repeated sequence region caller short tandom repeats (STR).
A. restriction enzymes are isolated from bacteria and our body do not have restriction enzymes, so this is not correct.
B. if offsprings have different numbers of chromosomes, than it must be numerical chromosomal abnormality. it do not have any connection with repeat numbers.
C.recombination leads to unequal exchange of genetic material between two arms of chromosomes, however our repear sequences are very small and have located on the telomeric or satellite region of chromosome. so this possiblity is also wrong.
D. these repeat sequences are transcribed more frequently, hence different individuals have different numbers of repeats. because it's transcription rate is different in different individuals and produces different numbers of repeats.
E. single nucleotide polymorphism produces SNP not repeats.