miRNAs are encoded in the genome as segments of longer transcripts. Their characteristic structure helps identify them and predict the target genes they might regulate. Which of the following are the characteristic features of these small RNA molecules?

I. The functional form of an miRNA is typically 21 or 22 nucleotides (it can vary from 19 to 25 nucleotides).

II. The first cleavage liberates the stem-loop, called the pre-miRNA; the second generates the mature miRNA from the pre-miRNA.

III. The pre-miRNAs can be encoded by any part of a transcript: that is, they might fall within coding regions, within leader regions, or within Introns.

IV. The base pairing between miRNA and target RNA is initiated by interactions of so-called seed residues—the sequence between bases 2 and 9 of the 22-nucleotide miRNA.

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#Question id: 15839

#Unit 8. Inheritance Biology

In the yeast cross of ade2 met14 his3 x + + +, a total of 120 tetrads are analyzed. The following tetrad types are found in the numbers shown below each tetrad. The markers ade2, met14, and his3 are abbreviated a, m, and h and the wild type allele of each gene is indicated by +.

 

Use this categorization and the numbers of each type to determine which (if any) of the three markers are linked. For any linked markers, calculate the distance between them in cM.      

To measure the distance between two linked His– mutations, you cross a his2– mutant to a his4– mutant and then dissect 100 tetrads. Your lab partner records which spore clones are His+ and which are His– ; but then the fool loses the papers on which most of the data is recorded. In the end all he can remember is that there were three different tetrad types an that there was only one tetrad of the type with 2 His+ and 2 His– spore clones.

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#Question id: 15840

#Unit 8. Inheritance Biology

In the yeast cross of ade2 met14 his3 x + + +, a total of 120 tetrads are analyzed. The following tetrad types are found in the numbers shown below each tetrad. The markers ade2, met14, and his3 are abbreviated a, m, and h and the wild type allele of each gene is indicated by +.

 

What were the other two types of tetrads (how many His+ and His– spores do they have)?

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#Question id: 15841

#Unit 8. Inheritance Biology

In the yeast cross of ade2 met14 his3 x + + +, a total of 120 tetrads are analyzed. The following tetrad types are found in the numbers shown below each tetrad. The markers ade2, met14, and his3 are abbreviated a, m, and h and the wild type allele of each gene is indicated by +.

 

Based on your numbers, calculate the distance between his2 and his4.

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#Question id: 15842

#Unit 8. Inheritance Biology

In the yeast cross of ade2 met14 his3 x + + +, a total of 120 tetrads are analyzed. The markers ade2, met14, and his3 are abbreviated a, m, and h and the wild type allele of each gene is indicated by +.

      

Given three locus from above, which locus shows the tetratype (T)

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#Question id: 15843

#Unit 8. Inheritance Biology

You have isolated two temperature-sensitive mutations in phage l that you suspect may be in the same gene. These phage mutants are called ts-1 and ts-2. Each mutant will form plaques at 35˚C but not at 42˚C. You cross ts-1 to ts-2 phage by coinfecting E. coli at the permissive temperature of 35˚C. When the resulting phage lysate is plated at 35˚C you count 10,000 plaques per ml of phage lysate, but when the same phage lysate is plated at 42˚C, there are only 80 plaques per ml.           What is the distance between the ts-1 and ts-2 mutations in m.u.?

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#Question id: 15844

#Unit 8. Inheritance Biology

You have isolated two temperature-sensitive mutations in phage l that you suspect may be in the same gene. These phage mutants are called ts-1 and ts-2. Each mutant will form plaques at 35˚C but not at 42˚C. You cross ts^-1 to ts^-2 phage by coinfecting E. coli at the permissive temperature of 35˚C. When the resulting phage lysate is plated at 35˚C you count 10,000 plaques per ml of phage lysate, but when the same phage lysate is plated at 42˚C, there are only 80 plaques per ml.  

If the total size of the phage is 5 x 10⁴ bp and the total genetic map length of the phage is 100 m.u., about how far apart are the mutations in base pairs?