The following points highlight the top four models proposed for chromosome structure. The models are: 1. Molecular Model 2. Multi-Stranded Model or Polyneme Chromosome Model 3. General Chromosome Model 4. Folded Fibre Model. Chromosome Structure: Model # 1. Molecular Model: This model of chromosome structure was proposed by Taylor and coworkers in 1957, 1963 and is based on the semiconservative [...]
In this article we will discuss about the translocation in humans. Interchanges are the most common structural chromosome changes reported in human. Partial sterility in interchange heterozygotes is infrequent due to the production of balanced gametes and as a result, interchanges in human are identifiable only through the analysis of karyotype, usually coupled with chromosome banding patterns. Various kinds of [...]
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) [...]