Centromere repositioning in mammals.

Area of Science:

• Genetics
• Evolutionary Biology
• Cytogenetics

Background:

• Comparative hybridization of bacterial artificial chromosome clones reveals centromere repositioning, a phenomenon where centromeres move along chromosomes without altering marker order.
• Evolutionary new centromeres (ENCs) are frequently observed across species, with significant instances in macaques, donkeys, and orangutans.
• Human neocentromeres arise from acentric fragments, leading to clinical phenotypes, while other repositioning events offer insights into ENC formation.

Purpose of the Study:

• To review the phenomenon of centromere repositioning and its evolutionary implications.
• To present new data on the population genetics of orangutan ENCs.
• To report the first instance of an ENC on the X chromosome of squirrel monkeys.

Main Methods:

• Comparative hybridization of large bacterial artificial chromosome clone panels.
• Population genetics analysis.
• Classical and molecular cytogenetic investigations.

Main Results:

• Centromere repositioning is a common evolutionary mechanism, with numerous ENCs identified in various primate and equid species.
• New data provides insights into the population genetics of ENCs in orangutans.
• An ENC has been identified on the X chromosome of squirrel monkeys, marking a novel discovery.

Conclusions:

• Centromere repositioning is a significant driver of chromosomal evolution.
• Classical and molecular cytogenetics remain indispensable for identifying centromere movements, even with advances in next-generation sequencing.
• The study of ENCs continues to expand, with new discoveries in diverse species and ongoing investigations into their genetic underpinnings.