Over 100 scientists from 16 institutions worked together for five years to
complete the massive and complex sugarcane genome. The crop's massive genome
was difficult to sequence because in the evolutionary history of sugarcane,
its genome was duplicated twice, resulting in four slightly different
versions of each pair of chromosomes all crammed into the same nucleus
together.

These events not only quadrupled the size of the genome, they also made
highly similar sequences from the genome wide duplication much more
difficult to assemble into distinct chromosomes. For this challenge, the
research team used high-throughput chromatin conformation capture (Hi-C).
When analyzed using ALLHIC, a customized algorithm developed by the team,
the resulting data provided a rough map of which sections of sequence most
likely belonged to which chromosome. By combining long sequence reads and
the Hi-C physical map, the researchers found which gene sequences belonged
to each of the four variations on the original, pre-duplications genome-a
much higher level of detail than they expected to attain.

Understanding these changes helped the researchers resolve the mystery why
Saccharum spontaneum (wild sugarcane) is such a superior source of disease
resistance and stress tolerance genes. The high quality genome sequence also
identified the possible origins of modern sugarcane's incredible sweetness:
accumulated mutations that produced multiple copies of genes for
sugar-transporting proteins.



[www.igb.illinois.edu]
ies-sugarcane-genome