Variation disappears when a new allele reaches the point of fixation—when it either disappears from the population or replaces the ancestral allele entirely.
Anmizlay itisujjil alwaq wa id allele eynayan ewad edag wan uɣin net - alwaq wa id itisujjil i ichaɣib meɣ itajjach edag n allele n kel aru fuk net