RNA polymerase performs two proofreading functions on that growing transcript. 

The first of these is called pyrophosphorolytic editing. In this, the enzyme uses its active site, in a simple back-reaction, to catalyze the removal of an incorrectly inserted ribonucleotide, by reincorporation of PPi. The enzyme can then incorporate another ribonucleotide in its place in the growing RNA chain. Note that the enzyme can remove either correct or incorrect bases in this manner, but spends longer hovering over mismatches than matches, and thus removes the former more frequently.

TLS Online TPP Program

#Id: 7339

#Unit 11. Evolution and Behavior

Positive assortative mating

Individuals' mate with others who are like themselves phenotypically for selected traits. The net effect of positive assortative mating is a progressive increase in the number of  homozygous genotypes (AA and aa)

TLS Online TPP Program

#Id: 7340

#Unit 11. Evolution and Behavior

TLS Online TPP Program

#Id: 7341

#Unit 11. Evolution and Behavior

Inbreeding

Preferential mating between related individuals. Inbreeding is more likely to take place in nature when population size becomes very small, and the number of mates is limited.

TLS Online TPP Program

#Id: 7342

#Unit 11. Evolution and Behavior

TLS Online TPP Program

#Id: 7343

#Unit 11. Evolution and Behavior

TLS Online TPP Program

#Id: 7344

#Unit 11. Evolution and Behavior

Inbreeding coefficient (F)

Probability that an individual has two identical alleles for a given gene. Inbreeding coefficients can range from 0 to 1.