Question

How are trisomics classified?

Answer 1

Trisomics:

1. Trisomics are nothing but aneuploids, carrying an extra chromosome to the normal somatic complement.
2. Trisomics are mainly classified as primary, secondary, and tertiary trisomics.
3. Primary trisomic is the one with the extra chromosome being normal in addition to 2 similar chromosomes of a bivalent.
4. A secondary trisomic is the one where the extra chromosome is an isochromosome (chromosome with two identical arms) involving one of the two arms of a normal chromosome.
5. Tertiary trisomic is the one with an extra chromosome that has segments from non-homologous chromosomes.