Telomereadjacent

Telomere-adjacent refers to DNA sequences located immediately next to the ends of linear chromosomes. These regions are collectively known as subtelomeres and extend from the telomeric repeats into the chromosome interior for varying distances across species. Telomere-adjacent DNA is often rich in repetitive elements and segmental duplications and tends to exhibit greater structural variation between individuals than many other genomic regions.

The organization of telomere-adjacent regions is influenced by telomere biology. Telomere position effect can spread heterochromatin from chromosome ends into subtelomeric DNA, modulating the expression of nearby genes. The region commonly shows elevated rates of recombination and rearrangement, fostering rapid genetic diversification. This variability is functionally significant in organisms that rely on dynamic surface proteins or antigenic variation, such as certain pathogen species that harbor telomere-adjacent gene families to evade host immunity. A well-known example is the var gene family in Plasmodium falciparum, which resides in subtelomeric, telomere-adjacent regions and contributes to immune evasion.

Because subtelomeric DNA is repetitive and structurally complex, sequencing and assembling telomere-adjacent regions pose technical challenges. Advances in long-read sequencing technologies, improved genome assemblies, and chromatin profiling have improved analysis of these regions. Studying telomere-adjacent DNA enhances understanding of chromosome end biology, genome evolution, and how chromosomal neighborhoods influence gene regulation and variation. See also subtelomere and telomere biology for related concepts.