It's been a while since my last class in genetics, so I've forgot most of it. However, I found myself studying human reproduction and I've the following doubt concerning spermatogenesis:
the process begins with a spermatogonium, a diploid cell (i.e. it contains 23 chromosomes and the corresponding homologous), which, through mitosis, generates the primary spermatocytes. The latter undergoes meiosis generating the two secondary spermatocytes; these are haploid, one of them contains 23 chromosomes and the other the corresponding homologous.
Since a chromosome A and its homologous B contain the same genes but with (generally) different alleles, the two secondary spermatocites have different genomes. Now, each of them splits into two equal cells (spermatids), through mitosis. My textbook says that the four spermatids have all different genomes, but shouldn't there be only two genomes?