What Happens to the MtDNA of Mice That Are Homozygous

question 14

Essay

What happens to the mtDNA of mice that are homozygous for the mutant gene called Polg? How do the "mutator" mice differ from their normal littermates? How do mice that are heterozygous for the Polg mutation differ from those that are homozygous for the Polg mutation? What should have happened to the life span of mice heterozygous for the Polg gene,if mtDNA mutations were a major contributor to the normal aging process? What do the above results of studies of the Polg mutation suggest about the relationship between mtDNA mutations and premature aging in animals?

---

Definitions:

Inhibitory Generalization Gradient

A graph showing the level of generalization from an inhibitory conditioned stimulus (CS1) to other stimuli.

Excitatory Generalization Gradient

The phenomenon in which the response to a stimulus spreads to similar stimuli, reflecting the degree of stimulus similarity.

Stimulus Contrast

The change in response strength or rate to a stimulus when the background or context stimuli are altered.

Stimulus Generalization

The process in psychology where a response that has been conditioned to a specific stimulus is also elicited by similar stimuli.