|MadSci Network: Genetics|
Recessive mutations are more easily detectable in bacteria mainly because they are haploid organisms. This means that they only have one "set" of genes. Diploid organisms (like humans) have two sets of genes. One is from the mother and one from the father. Therefore, in diploid organisms the recessive mutation may be masked by a dominant gene. Yeasts can have a diploid phase when they reproduce sexually. But often they grow asexually. Another factor to consider when looking at yeast and bacteria is that it is much easier to manipulate their environmental conditions in a laboratory setting. So, if you are looking for a recessive mutation that causes lactose (just an example) metabolism to not work, you can try growing these organisms in a media that contains only lactose as an energy source. The ones that will not grow have the mutation.
Try the links in the MadSci Library for more information on Genetics.