Short tandem repeat (STR) analysis uses DNA loci that vary in the number of repe

Question

Short tandem repeat (STR) analysis uses DNA loci that vary in the number of repeats to identify individuals. A set of 13 polymorphic loci, the CODIS loci, is used for identification in North America. One of the loci is CSF1PO, which has 4 base pair tandem repeats; the number of repeats varies from 5 to 16. The sequence of CSF1PO is shown in the STR csf1po file.

1.Using the PCR primers shown in the picture, what fragment length will be produced for an allele with 8 repeats? 13 repeats?

CSF1PO GenBank Sequence (Accession X14720) AACCTGAGTC TGCCAAGGAC TAGCAGGTTG CTAACCACCC TTGGACTCAG ACGGTTCCTG ATCGTCCAAC GATTGGTGGG TGTGTCTCAG TTTTCCTACC TGTAAAATGA AGATATTAAC ACACAGAGTC AAAAGGATGG ACATTTTACT TCTATAATTG 41 AGTAACTGCC TTCATAGATA GAAGATAGATAGATTAGATA TCATTGACGG AAGTATCTAT CTTCTATCTA TCTAATCTAT 81 3 4 5 8 9 10 GATAGATAGA TAGATAGATA GATAGATAGA TAGATAGATA ?????????? ?????????? ?????????? ?????????? 121 12 GATAGGAAGT ACTTAGAACA GGGTCTGACA CAGGAAATGC CTATCCTTCA TGAATCTTGT CCCAGACTGT GTCCTTTACG 161 TGTCCAAGTG TGCACCAGGA GATAGTATCT GAGAAGGCTC ACAGGTTCAC ACGTGGTCCT CTATCATAGA CTCTTCCGAG 201 AGTCTGGCAC CATGTGGGTT GGGTGGGAAC CTGGAGGCTG TCAGACCGTG GTACACCCAA CCCACCCTTG GACCTCCGAC 241 GAGAATGGGC TGAAGATGGC CAGTGGTGTG TGGAA CTCTTACCCG ACTTCTACCG GTCACCACAC ACCTT 281

Explanation / Answer

The given DNA sequence with 12 repeats would produce a PCR fragment of 315 bp size.

1 repeat = 4 bp

If there are 13 repeats, the product size = 315 + 4 = 319 bp

If there are 8 repeats, the product size = 315 - 16 = 303 bp

To differentiate these bands, we can perform DNA sequencing.

We can also use DNA native PAGE gel to distinguish these bands.

(A long, high percentage agarose gel also should be able to separate these fragments).

Related Questions

Navigate

• Browse (All)
• Browse S
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.