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) [...]
In this article we will learn about:- 1. Origin of Inversions 2. Types of Inversion 3. Effects 4. Uses. Origin of Inversions: Inversion was first discovered by Sturtevant in 1921 in Drosophila. Later it was detected in a wide variety of plant and animal species. Inversions occur spontaneously, and can be induced artificially. In many organisms, inversions are found in [...]
In this article we will discuss about the paracentric inversion in chromosome. Chromosome Pairing and Crossing Over: In paracentric inversions chromosome pairing occurs by loop formation in the inverted region; the centromere remains outside the loop. Crossing over in the loop causes the formation of dicentric chromatids which produce bridges at anaphase. Chromatid bridges may be formed at AI or [...]