Question

What is the role of the secondary constriction region in a chromosome?

Answer 1

Answer:

Explanation:

Primary Constriction from a cytological point of view, is considered the centromere. Actually centromere ( as it plays most important role in chromatid separation during anaphase ) is present within the primary constriction. Primary constriction is present in all chromosomes . Secondary constriction is seen at the chromosome in addition to primary constriction/centromere and it is not present in all chromosomes. Secondary constriction is also known as nucleolar organiser region(NOR) involved in the formation of nucleolus. It also contains the genes for rRNA synthesis and NOR occurs in SAT (satellite chromosome). The location of NOR or Secondary constriction is species specific as it plays most important role in karyology and cytotaxonomy.