Characterisation of Inactivation Domains and Evolutionary Strata in Human X Chromosome through Markov Segmentation

Ashwin Kelkar, Vivek Thakur, Ramakrishna Ramaswamy, Deepti Deobagkar, Sridhar Hannenhalli
2009 PLoS ONE  
Markov segmentation is a method of identifying compositionally different subsequences in a given symbolic sequence. We have applied this technique to the DNA sequence of the human X chromosome to analyze its compositional structure. The human X chromosome is known to have acquired DNA through distinct evolutionary events and is believed to be composed of five evolutionary strata. In addition, in female mammals all copies of X chromosome in excess of one are transcriptionally inactivated. The
more » ... ation of a gene is correlated with its ability to undergo inactivation, but correlations between evolutionary strata and inactivation domains are less clear. Our analysis provides an accurate estimate of the location of stratum boundaries and gives a high-resolution map of compositionally different regions on the X chromosome. This leads to the identification of a novel stratum, as well as segments wherein a group of genes either undergo inactivation or escape inactivation in toto. We identify oligomers that appear to be unique to inactivation domains alone.
doi:10.1371/journal.pone.0007885 pmid:19946363 pmcid:PMC2776969 fatcat:sfbusegfljfilhomcdjalwmrfm