Mouse quaking is caused by a recessive dysmyelination mutation (qk), which

Below is a figure that describes the splicing patterns in various genotypes of quaking and normal mice. Portions of brain MAG (myelin-associated glycoprotein) RNA (including exons 11, 12, and 13) from young (14-day) and adult (2-month) mice are represented. The relative concentration of each RNA is indicated in the gel diagram below. (Figure and data are modified from Wu, J., et al. 2002. Proc. Natl. Acad. Sci. 99: 4233–4238.)

Given this information, select all the true statements.

what is the answer?

According your data, the A and B are the young mice and C and D are adult mice. Where A and C lakes one allele, thus they encode low amount of protein. Hence, both young and adult mice encode low amount of mRNA, but the adult mice samples have same concentrations. Thus, Adult mice produce the same size and amount of mRNA regardless of whether they are qk/qk or +/qk (first statement is correct).

The second statement is also correct, because the Young mice A (+/qk) do not expresses mor amount of mRNA than the young mice B (qk/qk) with 12 th exon, hence young homozygous qk/qk mice are more likely to produce mRNAs with exon 12 than young heterozygous +/qk mice.

The third statement is incorrect, because B (qk/qk) young produce more mRNA than the two adults. Thus, young produce more mRNA than the adults.

The fourth statement is also correct, berceuse the 12 exon is not expressed by the adults; hence as mice age, the percentage of mRNAs containing exon 12 decreases.

The fifth statement is also correct because, in the gel the adults cannot express the mRNA with 11 and 13 exons, but they are expressed by the young’s. Hence, young mice produce two sizes of mRNA. Adult mice produce only one size of mRNA.

Hence, the correct statements are:

Adult mice produce the same size and amount of mRNA regardless of whether they are qk/qk or +/qk.
Young homozygous qk/qk mice are more likely to produce mRNAs with exon 12 than young heterozygous +/qk mice.
As mice age, the percentage of mRNAs containing exon 12 decreases.
Young mice produce two sizes of mRNA. Adult mice produce only one size of mRNA.