Interesting fact
Genomes of Great Apes and Humans are nearly the same, yet there is a huge cariotypic difference.
While Great Apes have chromosomes 2A and 2B, we have their fused version: human chromosome 2 (HSA2).
What do we do?
Together with Anna Gambin’s and Pawel Stankiewicz’s Labs we try to investigate the fusion event.
Using copmutational genomics, assembly of challenging genomic regions and time estimation we try to answer the following questions:
- Why did it happen: tracking the genomic mechanisms, genome organisation and structural properties that triggered the fusion event.
- When the HSA fusion event occured: time estimation based on Great Apes and Homo Sapiens genomes properties.
- What are the consequences: discovering the genomic content that was lost during the fusion event.
related publications
Revised time estimation of the ancestral human chromosome 2 fusion
BMC Genomics
2022
Background:
The reduction of the chromosome number from 48 in the Great Apes to 46 in modern humans is thought to result from the end-to-end fusion of two ancestral non-human primate chromosomes forming the human chromosome 2 (HSA2). Genomic signatures of this event are the presence of inverted telomeric repeats at the HSA2 fusion site and a block of degenerate satellite sequences that mark the remnants of the ancestral centromere. It has been estimated that this fusion arose up to 4.5 million years ago (Mya).
Results:
We have developed an enhanced algorithm for the detection and efficient counting of the locally over-represented weak-to-strong (AT to GC) substitutions. By analyzing the enrichment of these substitutions around the fusion site of HSA2 we estimated its formation time at 0.9 Mya with a 95% confidence interval of 0.4-1.5 Mya. Additionally, based on the statistics derived from our algorithm, we have reconstructed the evolutionary distances among the Great Apes (Hominoidea).
Conclusions:
Our results shed light on the HSA2 fusion formation and provide a novel computational alternative for the estimation of the speciation chronology.