Summary
Individual chromosomes occupy distinct regions of the nucleus, influencing genome organisation and expression.
In depth
Each chromosome occupies a discrete region, with gene-rich chromosomes tending to sit toward the centre. Hi-C mapping reveals topologically associating domains (TADs) that restrict enhancer-promoter contact, insulated by CTCF and cohesin.
Disrupting TAD boundaries can cause disease.
Territories were first suggested by Carl Rabl and Theodor Boveri and demonstrated with chromosome painting by FISH in the 1980s. Chromatin loops from different territories can intermingle at their edges, and genes can loop out of their territory on activation. Hi-C and related methods map contacts genome-wide, showing A compartments (active) and B compartments (inactive) as well as TADs, formed by loop extrusion by cohesin and blocked by CTCF.
Nuclear position matters: heterochromatin sits near the nuclear lamina, active genes near speckles, and in rod photoreceptors of nocturnal mammals the arrangement is inverted to channel light. Disruption of TAD boundaries can cause limb malformations and cancer by connecting enhancers to wrong genes.
Frequently asked questions
What is Chromosome Territories?
Individual chromosomes occupy distinct regions of the nucleus, influencing genome organisation and expression.
Which area of biology covers Chromosome Territories, and how advanced is it?
Chromosome Territories is one of the 52 topics in Molecular Biology. It is rated Advanced, so it suits learners who want specialist depth. Related topics in this area include Enhancers and Silencers, Transcription Factors, DNA Methylation.
Why does Chromosome Territories matter?
The 3D organisation of the genome is a layer of gene regulation, in addition to the sequence.
Can you give an example of Chromosome Territories?
Boundary deletions near limb genes cause malformations.
What should I learn before Chromosome Territories?
Work through the Beginner topics in Molecular Biology first, such as Central Dogma, DNA Replication, Base Pairing, then return to Chromosome Territories. Advanced topics assume the Intermediate vocabulary.
What topics are related to Chromosome Territories?
The closest topics to Chromosome Territories are Enhancers and Silencers, Transcription Factors, DNA Methylation, Gene Expression. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Chromosome Territories?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Chromosome Territories. To practise the whole of Molecular Biology, use the Molecular Biology quiz.
How is Chromosome Territories different from Enhancers and Silencers?
Chromosome Territories: Individual chromosomes occupy distinct regions of the nucleus, influencing genome organisation and expression. Enhancers and Silencers: Distant regulatory DNA elements that increase or decrease transcription via looping to the promoter. Read both side by side and note what each one explains.
How should I study Chromosome Territories step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Enhancers and Silencers and explain the difference aloud. Finally, take the Molecular Biology quiz and come back to this page for any question you miss.