In this article we will discuss about:- 1. Origin and Occurrence of Triploids 2. Chromosome Pairing and Chiasma Formation in Auto-Triploids 3. Fertility of Auto-Triploids 4. Pneotypic Effects of Auto-Triploidy. Origin and Occurrence of Triploids: (i) Triploids originate from hybridization between auto-tetraploids (4x) and diploids (2x). The autotetraploid produces diploid (2a) gametes which when fertilized by a normal monoploid (x) [...]
The following points highlight the five main types of trisomics which is a cell tissue or individual possessing the extra chromosome. The types are: 1. Primary Trisomics 2. Secondary Trisomics 3. Telocentric or Telosomic or Telotrisomics 4. Tertiary Trisomics 5. Compensating Trisomics. Type # 1. Primary Trisomic: In this type of trisomic, the extra chromosome is normal and completely homologous [...]
In this article we will discuss about the aneuploidy in animals. Aneuploidy of sex chromosomes and autosomes have been reported in several animals. Nondisjunction is major source of aneuploid gametes Sturtevant reported that trisomic for chromosome 4 (triplo-IV) in Drosophila melanogaster ABCDEFGH was fertile in the female sex. In mouse, trisomics were found to be sterile or semi-sterile, but their [...]