Question

What kinds of materials obtained from a crime scene might contain DNA? (2 pts)

Consider the following DNA molecule

5ʹ CCTTGGGGCCAATTGGCCGTACCGAATTCGCCGAATTCCGGAATTGGCCTACGGGCTCGGGCCGG 3ʹ

3ʹ GGAACCCCGGTTAACCGGCATGGCTTAAGCGGCTTAAGGCCTTAACCGGATGCCCGAGCCCGGCC 5ʹ

How many bp is the original fragment? (1 point)

The enzyme HaeIII has the following restriction site    5ʹ GG˅CC 3ʹ          

                                                                                3ʹ CC˄GG 5ʹ

If digested with HaeIII, how many fragments are formed if the DNA is linear? (1 point)

If digested with HaeIII, how many fragments are formed if the DNA is circular? (1 point)

Consider the following DNA molecule

5ʹ ATTCGCGAATTCGGTACCGAATTGGCAGATTCGCCGAATTCCCGTACGGAATTAGTTAAC 3ʹ

3ʹ TAAGCGCTTAAGCCATGGCTTAACCGTCTAAGCGGCTTAAGGGCATGCCTTAATCAATTG 5ʹ

How many bp is the original fragment? (1 point)

(Recognition site for EcoRI is given previously)

If digested with EcoRI, how many fragments are formed if the DNA is linear? (1 point)

If digested with EcoRI, how many fragments are formed if the DNA is circular? (1 point)

Using the results from question #2 (for linear DNA), draw the results on a gel( “—“ = the well). Well A contains the complete, intact, undigested sample/sequence; well B contains digested sample/sequence. (4 points)

A                 B

Answer 1

1) Teeth, hair, blood, semen and various body fluids can be found in the objects used in the crime scene. Therefore, such objects are collected carefully which may have blood stains, hair, semen, vaginal fluids, tissues or any other fluids.

2a) 65 bp (Base Pairs).

5? CCTTGGGGCCAATTGGCCGTACCGAATTCGCCGAATTCCGGAATTGGCCTACGGGCTCGGGCCGG 3?

3? GGAACCCCGGTTAACCGGCATGGCTTAAGCGGCTTAAGGCCTTAACCGGATGCCCGAGCCCGGCC 5?

Adenine pairs with thymine (A-T or T-A) and guanine pairs with cytosine (G-C or C-G). Count one strand to find number of bases and the total is equal to bases on other strand. Therefore, number of base pair

Enzyme HaeIII - restriction site - 5? GG?CC 3?   

3? CC?GG 5?

The enzyme cuts at GG and CC in 5' to 3' strand and at CC and GG in 3' to 5' strand.

(2b) if the DNA is linear : Number of fragments = 5

5? CCTTGGGGCCAATTGGCCGTACCGAATTCGCCGAATTCCGGAATTGGCCTACGGGCTCGGGCCGG 3?

3? GGAACCCCGGTTAACCGGCATGGCTTAAGCGGCTTAAGGCCTTAACCGGATGCCCGAGCCCGGCC 5?

The enzyme cuts the linear DNA at four sites and the resulting fragment number is 5.

(2c) if the DNA is circular : number of fragments = 4

The enzyme cuts the circular DNA at four sites and the resulting fragment number is 4.

Gel :