Topic Evolution and Diversity: Q) Besides crossing over and independent assortment of pairs of homologous chromosome during meiosis, what are the other sources of genetic variation in a sexually reproducing population?

Ans: 
i) Gene and chromosomal mutation, 
ii) gene flow via migration of individuals into the population, 
iii) random mating between individuals within the population, and 
iv) random fusion of gametes during sexual fertilization.