▁grow ▁the ▁organ ism ▁into ▁ad ul th ood , ▁before ▁they ▁go ▁their ▁separate ▁ways ▁in ▁bodies ▁of ▁the ▁organ ism ' s ▁pro gen y . ▁Bod ies ▁are ▁created ▁and ▁disc arded , ▁but ▁good ▁gen es ▁live ▁on ▁as ▁rep lic as ▁of ▁themselves , ▁a ▁result ▁of ▁a ▁high - f idel ity ▁copy ▁process ▁typical ▁of ▁digital ▁encoding . ▁ ▁Through ▁me ios is ▁( sex ual ▁reprodu ction ), ▁gen es ▁share ▁bodies ▁with ▁different ▁companion ▁gen es ▁in ▁success ive ▁gener ations . ▁Thus ▁gen es ▁can ▁be ▁said ▁to ▁flow ▁in ▁a ▁river ▁through ▁ge ological ▁time . ▁Even ▁though ▁gen es ▁are ▁self ish , ▁over ▁the ▁long ▁run ▁every ▁gene ▁needs ▁to ▁be ▁compatible ▁with ▁all ▁other ▁gen es ▁in ▁the ▁gene ▁pool ▁of ▁a ▁population ▁of ▁organ isms , ▁to ▁produce ▁successful ▁organ isms . ▁ ▁A ▁river ▁of ▁gen es ▁may ▁fork , ▁mostly ▁due ▁to ▁the ▁ge ographical ▁separation ▁between ▁two ▁populations ▁of ▁organ isms . ▁Because ▁gen es ▁in ▁the ▁two ▁branches ▁never ▁share ▁the ▁same ▁bodies , ▁they ▁may ▁dr ift ▁apart ▁until ▁gen es ▁from ▁the ▁two ▁branches ▁become ▁in compatible . ▁Organ isms ▁created ▁by ▁these ▁two ▁branches ▁form ▁separate , ▁non - inter bre eding ▁species , ▁comple ting ▁the ▁process ▁of ▁spe ci ation . ▁ ▁All ▁Africa ▁and ▁her ▁pro gen ies ▁▁ ▁When ▁trac ing ▁human ▁line age ▁back ▁in ▁time , ▁most ▁people ▁look ▁at ▁parents , ▁grand par ents