An R loop experiment was performed on two different mRNA's. The first showed one R loop, while the second showed two R loops separated by a region of double-stranded DNA. What is the composition of these two mRNA's?
A)The first contains no introns and the second two introns
B)The first contains no introns and the second one intron
C)The first contains one intron and the second two introns
D)The first contains two introns and the second one intron

Question

Quizplus · Accepted Answer

The presence of R loops suggests that the mRNA has an RNA-DNA hybrid structure, indicating the presence of a single-stranded RNA region that has hybridized with the complementary DNA strand. In the first mRNA, there is only one R loop, indicating the presence of only one single-stranded region. This suggests the absence of introns since introns are usually flanked by both single-stranded and double-stranded regions due to splicing. In the second mRNA, there are two R loops separated by a region of double-stranded DNA, indicating two single-stranded regions. This suggests the presence of one intron, as introns are usually flanked by both single-stranded and double-stranded regions due to splicing. Therefore, the correct answer is option B - the first mRNA contains no introns, and the second mRNA contains only one intron.

An R Loop Experiment Was Performed on Two Different MRNA's