BIOL 2400 Lecture Notes - Lecture 6: Motility, Selective Breeding, Hangingfly
Document Summary
The combining and mixing of chromosomes during offspring production: meiosis and recombination, fertilization. Mulle(cid:396)"s rat(cid:272)het: original, mutation 1, mutation 2. The process by which asexual genomes accumulate deleterious mutations: deleterious mutations can be purged from sexuals through recombination. E(cid:454) ge(cid:374)e(cid:396)ates (cid:373)o(cid:396)e ge(cid:374)eti(cid:272) (cid:448)a(cid:396)iatio(cid:374) that helps (cid:862)out-(cid:396)u(cid:374)(cid:863) pa(cid:396)asites. Sexual reproduction creates more genetic variation: allows for faster evolution, need to constantly outrun evolving parasites, biological arms race between hosts and parasites, h(cid:455)pothesis: se(cid:454)ual (cid:396)ep(cid:396)odu(cid:272)tio(cid:374) helps spe(cid:272)ies to (cid:862)out-(cid:396)u(cid:374)(cid:863) pa(cid:396)asite (cid:862)red quee(cid:374) effe(cid:272)t(cid:863) (cid:894)va(cid:374) vale(cid:374) 1973(cid:895) Cost vs. benefits of sec: costs, twofold cost of sex, search cost, reduced relatedness with offspring, risk of sexually transmitted disease, benefits, combining beneficial mutations, generate new genotypes, faster evolution, purging of deleterious mutations. Sex is the combining and mixing of chromosomes during offspring production: meiosis and recombination, fertilization. Sex creates new genetic variation by mixing parental alleles.