Primate chromosome evolution: with reference to marker order and neocentromeres.

Area of Science:

• Genomics
• Evolutionary Biology
• Cytogenetics

Background:

• Chromosomal homology determination was speculative before molecular cytogenetics.
• Early comparative cytogenetics relied on less precise methods for understanding chromosome evolution.

Purpose of the Study:

• To review advancements in molecular cytogenetics for comparative genomics.
• To highlight how new techniques illuminate mammalian chromosome evolution and ancestral karyotypes.
• To explore the role of centromere shifts in genomic evolution.

Main Methods:

• Chromosome sorting via flow cytometry and degenerate oligonucleotide primed-PCR (DOP-PCR) for chromosome painting.
• Comparative chromosome painting to hypothesize ancestral mammalian karyotypes.
• Hybridization with cloned DNA and Bacterial Artificial Chromosome-Fluorescence In Situ Hybridization (BAC-FISH) for intrachromosomal rearrangement analysis and marker ordering.

Main Results:

• Molecular cytogenetics significantly advanced comparative chromosome painting.
• Comparative painting enabled robust hypotheses of ancestral mammalian karyotypes and evolutionary routes.
• BAC-FISH revealed marker order, syntenies, and associations, identifying frequent centromere shifts (evolutionary new centromeres).

Conclusions:

• Evolutionary chromosome painting provides critical insights into mammalian genome evolution.
• Centromere shifts are significant drivers of chromosome evolution.
• An evolutionary perspective explains contemporary genomic phenomena like clinical neocentromeres.