Question

What are the causes and effects of genetic variation in human?

Answer 1

this is caused by synapsis

Explanation:

is the pairing of two homologous chromosomes that occurs during meiosis.
It allows matching-up of homologous pairs prior to their segregation, and possible chromosomal crossover between them. Synapsis takes place during prophase I of meiosis.
When homologous chromosomes synapse, their ends are first attached to the nuclear envelope. These end-membrane complexes then migrate,