If a species which droped to around fifty individuals then was put ont he endangered species list and grew?

Question

to thousands , would the genetic variability be high or low?

Answer 1

Genetic variability decreases when the number of individuals decreases. If population size is very low, an "evolutionary bottleneck" occurs: because of genetic drift, some alleles (=versions of a gene) will be lost, while some will become fixed in the population.
This phenomenon has been actually recorded in several natural populations that have been,at some point in their history, reduced to few individuals.
See here for a more detailed explanation:
http://virtuallaboratory.net/Biofundamentals/lectureNotes/Topic1H_Evo.htm

Answer 2

Low variability. This is one of the dangers of letting species drop to such low levels. For some, there is a "point of no return", regardless of the amount of protection that can be afforded them.

Answer 3

Low - the descendants of fifty will have much less variation than the descendants of thousands or millions.

Answer 4

Very low. You would expect deleterious recessives to be expressed as a result of inbreeding -- as we see in the Florida panther, which is functionally extinct.