A cikin mutane, alal misali, launin ido shine halayyar da aka gada kuma mutum zai iya gadon "halayyar launin ruwan kasa" daga ɗayan iyayensu. Abubuwan da aka gada suna sarrafawa ta hanyar kwayoyin halitta da kuma cikakkiyar tsari na kwayoyin halitta a cikin kwayoyin halitta (kayan kwayoyin halitta) ana kiransa genotype. An kira cikakkiyar tsari na halayen da aka gani wanda ke samar da tsari da halayyar kwayoyin halitta da phenotype. Wadannan halaye sun fito ne daga hulɗar genotype tare da yanayin. A sakamakon haka, yawancin bangarori na kwayoyin halitta ba a haifa ba. Alal misali, fata mai launin fata ta fito ne daga hulɗar da ke tsakanin mutum da genotype na hasken rana; saboda haka ba a ba da sunadarai ga wasu mutane ba. Duk da haka, idan nau'in DNA yana canzawa a cikin nau'i guda na DNA, bambancin da ke faruwa a cikin nau'i guda biyu na DNA yana iya haifar da bambancin da ke faruwa a cikin nau'i guda biyu na kwayoyin halitta, wanda ya haifar da bambancin da ke faruwa a cikin nau'i guda biyu na kwayoyin halitta. Idan DNA
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