Can two normal individuals of the same species with sexual reproduction have identical genomes and identical karyotypes? How is the human karyotype usually represented?

Answer 1

It is possible for two individuals of the same species with sexual reproduction to have identical genomes as is the case with monozygotic twins. However, aside from monozygotic twins, the likelihood of two humans having the same genotype is statistically impossible given that there are 20,000-25,000 genes in the human genome all of which are susceptible to mutations and translocation/nondisjunction during meiosis. The fewer genes an organism has, the more likely the possibility of having two members of the species with the same genome.

A karyotype is an image of all 22 pairs of homologous chromosomes (one from the mother and one from the father) as well as the two sex chromosomes (XX for female and XY for male with the Y being much shorter than the X).