Principles of Genetics and Breeding

5.1.7.1 Karyological characters

One of the easiest way is to estimate the size of erythrocyte nuclei, supplying a good indication of the ploidy and something hybrid nature of the animals.

• A direct estimation of the DNA content of the nuclei by cytophotometry can be applied to reveal several levels of ploidy among the hybrids.
• Furthermore, study of karyotypes allows one to define accurately the genetic structure of the individual.
• In most cases, the hybrid presents the two haploid sets of chromosomes of the parental species, and can thus be identified as a diploid hybrid.
• In the case of polyploidy hybrids,study of the karyotype reveals the importance of the two parental contributions.