What maintains the frequencies of human genetic diseases?
D000755:Anemia, Sickle Cell / Q000235:genetics; D003920:Diabetes Mellitus / Q000235:genetics; D005260:Female; D005787:Gene Frequency; D030342:Genetic Diseases, Inborn / Q000235:genetics*; D006432:Hemochromatosis / Q000235:genetics; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D008297:Male; D012641:Selection, Genetic; D013106:Sphingolipidoses / Q000235:genetics