August 28, 2012, Shenzhen, China The international research team led by Chinese Academy of Agricultural Sciences and BGI have completed the genome sequence and analysis of a diploid cotton-- Gossypium raimondii. The cotton genome provides an invaluable resource for the study and genetic improvement of cotton quality and output, and sheds new lights on understanding the genetic characteristics and evolutionary mechanism underlying cotton and its close relatives. The study was published online in Nature Genetics. (http://www.nature.com/ng/journal/vaop/ncurrent/full/ng.2371.html).
Cotton, also known as "white gold", is an important cash crop worldwide. Its fiber is one of the oldest fibers under human cultivation, which traces over 7,000 years old recovered from archaeological sites. The cotton production provides income for approximately 100 million families, and approximately 150 countries are involved in cotton import and export. Additionally, in scientific research, cotton also serves as an excellent model system for studying polyploidization, cell elongation and cell wall biosynthesis.
In this study, researchers sequenced the genome of G. raimondii by the next-generation sequencing technology, yielding a draft cotton genome with 103.6-fold genome coverage. Over 73% of the assembled sequences were anchored on 13 G. raimondii chromosomes. They identified 2,355 syntenic blocks in the G. raimondii genome, and found that approximately 40% of the paralogous genes were present in more than 1 block, which suggests that this cotton genome has undergone substantial chromosome rearrangement during its evolution.
Through comprehensive comparison and analysis, researchers observed that one paleohexaploidization event occurred in the G. raimondii genome at approximately 130.8 million years ago, while the event is commonly fo
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