The following points highlight the fourteen main factors affecting crossing over and chiasma formation. The factors are: 1. Temperature 2. Age 3. Water Content 4. Sex 5. Nutritional Effects 6. Chemicals 7. Radiations 8. Shift in Population 9. Variation within the Organism 10. Chromosome Structure 11. Interference 12. Heterochromatin 13. Centromere 14. Genetic Effects. Crossing Over and Chiasma Formation: Factor [...]
The following points highlight the two main ways of representing chromosome set of species. The ways are: 1. Karyogram 2. Idiogram or Idiotype. Representing Chromosome: Way # 1. Karyogram: Photomicrographs of the chromosomes of a single representative somatic metaphase cell are clipped out and arranged in homologous pairs according to their size. If the chromosomes are small and there is [...]
The below mentioned article provides a short note on mitotic crossing over. Crossing over not only occurs during meiosis but also during mitosis. In individuals heterozygous for a gene producing a visible phenotype, somatic crossing over leads to the production of "twin spots" of dominant and recessive phenotypes. Mitotic crossing over was first discovered in Drosophila by Stern in 1936, [...]