Genes as well as chromosomes are transferred from generation to generation without any change.
In diploid cells, chromosomes occur in homologus pairs. Genes also occur in allelic pairs.
Both chromosomes as well as alleles follow law of segregation.
Prior to cell division, each chromosomes as well as allele of a gene gets replicated.
Both segregate during gamete formation or meiosis so that a gamete comes to have only one chromosome and one allele of each pair.
Fusion of the haploid gametes restores the diploid number as well as allelic pairs in the offspring.