Biol/ MBIOS 301 Quiz #7

Genetics 301 Quiz #7
Spring 2003
Class week 9

You can detect genetic polymorphisms in humans by adding two primers to a small sample of genomic DNA and amplifying the region between the primers using the PCR (polymerase chain reaction) method. The variation which is detected is often related to variations in the numbers of short repeat sequences (microsatellites) located between the primers. The variation is then detected by agarose gel electrophoresis, with larger fragments running more slowly (closer to the origin) than small pieces.

If Ethel is the mother of the child, which is the more likely father, Fred or Joe? Justify your answer. (Assume that all the variation in these individuals is related to variation in the number of repeats).

Individual	Allele detected	Band size after PCR
Fred	1	500
Fred	2	800
Ethel	1	550
Ethel	2	600
Joe	1	600
Joe	2	700

Ethel’s child Alleles detected: 500 and 600 bp.

Fred is the most likely father. The child must have gotten one allele from the mother (Ethel) and it must have been the 600 bp allele because the 550 bp allele is not present in the child. The other allele in the child,500 bp, is present in Fred but not in Joe.

2. Using the genetic code table below, list the possible single base substitution mutations that could take place from a GGA (glycine) codon, and which are silent, missense and nonsense mutations.

Possible single base substitutions:

UGA stop codon nonsense

CGA arg missense

AGA arg missense

GUA val missense

GCA ala missense

GAA glu missense

GGU gly silent

GGC gly silent

GGG gly silent

Genetics 301 Quiz #7 Spring 2003 Class week 9

Genetics 301 Quiz #7
Spring 2003
Class week 9