|Collecting the Clues
CHORI Scientists Link Specific Genetic Sequence to the Emergence of a Novel Centromere
CHORI scientists Lucia Carbone, PhD, and Pieter de Jong, PhD, of the CHORI Center for Genetics, along with their colleagues at the Department of Genetics and Microbiology at the University of Bari, Italy, have published a new study in Chromosoma reporting the first time association of a specific genetic sequence with the emergence of an evolutionary new centromere, or ENC.
“We were studying the evolutionary history of chromosome 18, comparing it in different primates, and we noticed there was an ENC. When we looked for genomic sequences in that region we noticed there was a clone gap in that family, and we found that intriguing,” says Dr. Carbone.
Centromeres are regions within a chromosome that are necessary for the correct segregation of that chromosome during cell division. Where and how centromeres originally emerge, however, is up for debate, and has resulted in an intense amount of scrutiny on ENCs - new centromeres that suddenly appear in a different region than where it previously had occurred.
"When new centromeres first appear in a chromosome, it's like a seed" says Dr. Carbone. "We don't know why or how, only that once the seeding starts, that centromeric sequence begins to function."
In the latest Chromosoma study, Dr. Carbone and her colleagues were able to identify that a human clone gap - a break in the assembled human genome map for which no sequence is known - corresponded to an ENC in Old World Monkeys (OWM).
"It was very difficult and painstaking, but eventually we were able to partially sequence the clone gap, which indicated a satellite-like, or repeat DNA sequence, that was uncloneable," explains Dr. Carbone.When Dr. Carbone and her colleagues then compared DNA sequences between OWM and the macaque and the marmoset, they found the same satellite-like sequences occurring in both species, but in different locations.
Tuesday, May 17, 2011 8:19 AM