Copy number variation-based polymorphism in a new pseudoautosomal region 3 (PAR3) of a human X-chromosome-transposed region (XTR) in the Y chromosome
A 3.5-Mb region of the X chromosome underwent duplication and transposition to the Y chromosome ~5–6 Mya. This X-transposed-region (XTR) originated at Xq21.3 and was inserted at Yp11.2. The two locations have 98.78 % homology and a high concentration of tandem repeats. In whole-genome scans of ten large families with dyslexic members, we identified transposed blocks comprising >102 kb of the Yp11.2 region in its homologous region at Xq21.3 in three females from three different families. Although recombination is known to be limited only to the pseudoautosomal regions (PARs) of the X and Y chromosomes, we report allelic unequal recombination between the XTR region Yp11.2 and Xq21.3, indicating the presence of a new PAR, which we named PAR3. This PAR3 region was also found in 2 % of the general population. An additional layer of justification could be provided from six other dyslexic cases which harbored duplications and deletions in the same Xq21.3 and Yp11.2 regions through allelic unequal recombination.
KeywordsPAR1 PAR2 CNV X-transposed region Yp11.2 Xq21.3 PAR3
We thank the subjects and their families for participating in this study; Prof. H. A. Ranganath for his help and encouragement; Marita J, Anand S, and Shyamala K.V. for their help in sample collection; the services of Vimta Labs Ltd.; University of Mysore for providing facility to conduct this work; and the Department of Science and Technology—Health Science (SR/SO/HS-103/2007) for funding, Government of India, New Delhi.
Written consent was obtained from all participants involved in this study and the Institutional Human Ethical Committee (IHEC no. 3/RI/2008-09) approved the consent procedure.
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