Systemic lupus erythematosus, often abbreviated as SLE or lupus, is a systemic autoimmune disease (or autoimmune connective tissue disease) in which the bodyâs immune system mistakenly attacks healthy tissue.ystemic lupus erythematosus, often abbreviated as SLE or lupus, is a systemic autoimmune disease (or autoimmune connective tissue disease) in which the bodyâs immune system mistakenly attacks healthy tissue.
Natural selection will only cause evolution if there is enough genetic variation in a population. Before the discovery of Mendelian genetics, one common hypothesis was blending inheritance. But with blending inheritance, genetic variance would be rapidly lost, making evolution by natural selection implausible.
The newly emerged viruses have the potential to cause epidemics or pandemics, since very few, if any, humans possess immunity against the new antigens. 1  Antigenic shift occurs because influenza A viruses have a large animal reservoir, consisting primarily of wild aquatic birds (e.g., ducks). It also occurs because the RNA genome of influenza A viruses is in the form of eight segments, which during viral replication are susceptible to a type of genetic exchange known as genetic reassortment.