Sexual selection impart new gene combinations to the individuals by the process of gamete formation and random fertilization of gametes.
Natural selection favors the beneficial variations that impart survival and/or reproductive fitness to the individuals. This results of evolution of population consisting of better adapted individuals.
For example, natural selection favors the bacteria with antibiotic resistance genes if antibiotics are present in surroundings.
<span> (1) gene frequencies may be changed by migration, gene flow from another population. (2) in small populations, gene frequencies can be changed via random sampling -- this is known as genetic drift. (3) mutation pressure and (4) non-Mendelian segregation (meiotic drive) may also change gene pools. However, by far the most important agent of evolution is (5) natural selection, which operates by </span>differential reproductive success<span> of individuals.
This disease is more common in African Americans and
females. Contractures of the fingers are classic for systemic lupus
erythematosus. The butterfly rash on the face is common, occurring in up to 40%
of affected individuals. Joint involvement is common. Pain is generally more
profound in the morning.