The below mentioned article provides a close view on the Polyploidy and Evolution of Species. The polyploidy has played an important role in evolution of new varieties and species in nature. Angiosperms and Pteridophytes have very high numbers of polyploid species in nature. More than 35 per cent angiosperms are polyploids. According to Manton (1950), among all the plant groups, [...]
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 [...]