Q23

Criteria	Marks
• Demonstrates a clear understanding of gel electrophoresis.	4
• Clear conclusion with breeding recommendation - Male (M2)<br>• Explains how this would be useful in selecting mates for a breeding program to increase variation.	2
• Recommends Male 2 for breeding with support OR<br>• Explains how gel electrophoresis would be useful in breeding program	3
• Identifies Male 2 for breeding<br>• Identifies the role/process of gel electrophoresis	2
• Some relevant information	1

Sample answer:

Gel electrophoresis is a technique used to separate DNA fragments according to their size. By comparing individuals in a population, the number of similarities and level of relatedness can be determined. This genotypic assay can be used to select mates with variation in the offspring. Male 2 (M2) would be the best recommendation for the breeding program based on the greater number of variations as seen in the gel electrophoresis. M1 and M3 have more similarities with F which my leave the offspring susceptible to selection pressures. Comments Using gel electrophoresis, we can see how many different DNA fragments are present in a sample and how large they are relative to one another. A DNA marker (also known as a size standard or a DNA ladder) is loaded into the first well of the gel. The fragments in the marker are of a known length so can be used to help approximate the size of the fragments in the samples. Many selected the wrong mate but gave valid justification. Not looking for variation from the marker but variation from F (female). Question is a justification of us, you do not need an explanation of the use. There is no connection in the stimulus between bands and desirable traits. Only variation. Range 1-4 Avg. 2.81