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.
Mutations may be caused by natural events within the environment, by action or inaction of deoxyribonucleic acid (DNA) repair enzymes , and by human production of chemicals or high-energy radiation (mutagens). Mutation rates vary from organism to organism, from gene to gene, from time to time, and from place to place.