Prof. He Xionglei of Sun Yat-sen University paid a visit to Institute of Hydrobiology, Chinese Academy of Sciences (IHB) on April 11.

On April 11, Prof. He Xionglei of Sun Yat-sen University gave a presentation entitled "The expression output of a single X chromosome" for researchers and graduate students of Institute of Hydrobiology, Chinese Academy of Sciences (IHB).

In 1967, Ohno presented a famous sex chromosome dosage compensation hypothesis. The mammalian sex chromosome (XX or XY) originated from a pair of autosomal, and in the evolution process, the Y chromosome gradually degraded and the gene expression of single X chromosome will be doubled, and another X will be silenced in female. A key step about this hypothesis is the double expression of single X chromosome, and the study results using microarray data support the Ohno hypothesis.

However, the microarray technology has its disadvantage in measuring the gene expression, especially the accuracy and breadth. Did the microarray data give the true answer? Prof. He’s lab used the RNA-Seq data (more accurate in measuring gene expression) to investigate the gene expression output in the X chromosome, and found most of gene in X chromosome have not double its expression when comparing the autosomals, thus refuted the classical the Ohno dose of compensation hypothesis.

Prof. He is currently a professor at the School of Life Sciences, Sun Yat-sen University. He has served as ad hoc Reviewer in the Journal of Molecular Biology & Evolution, PLoS Genetics, PLoS Computational Biology, PLoS One. More than 10 papers with first or corresponding author have been published in the journals, including the journal Science, Nature Genetics, Current Biology, PLoS Genetics, Molecular Biology & Evolution, etc.