Document Type
Article
Publication Date
1-1-2019
Publication Title
G3: Genes, Genomes, Genetics
Abstract
Ohno’s hypothesis predicts that the expression of the single X chromosome in males needs compensatory upregulation to balance its dosage with that of the diploid autosomes. Additionally, X chromosome inactivation ensures that quadruple expression of the two X chromosomes is avoided in females. These mechanisms have been actively studied in mice and humans but lag behind in domestic species. Using RNA sequencing data, we analyzed the X chromosome upregulation in sheep fetal tissues from day 135 of gestation under control, over or restricted maternal diets (100%, 140% and 60% of National Research Council Total Digestible Nutrients), and in conceptuses, juvenile, and adult somatic tissues. By computing the mean expression ratio of all X-linked genes to all autosomal genes (X:A), we found that all samples displayed some levels of X chromosome upregulation. The degrees of X upregulation were not significant (P-value = 0.74) between ovine females and males in the same somatic tissues. Brain, however, displayed complete X upregulation. Interestingly, the male and female reproduction-related tissues exhibited divergent X dosage upregulation. Moreover, expression upregulation of the X chromosome in fetal tissues was not affected by maternal diets. Maternal nutrition, however, did change expression levels of several X-linked genes, such as sex determination genes SOX3 and NR0B1. In summary, our results showed that X chromosome upregulation occurred in nearly all sheep somatic tissues analyzed, thus support Ohno’s hypothesis in a new species. However, the levels of upregulation differed by different subgroups of genes such as those that are house-keeping and “dosage-sensitive”.
Recommended Citation
Duan, Jingyue (Ellie); Flock, Kaleigh; Jue, Nathanial; Zhang, Mingyuan; Jones, Amanda; Al Seesi, Sahar; Mandoiu, Ion; Pillai, Sambhu; Hoffman, Maria; O’Neill, Rachel; Zinn, Steven; Govoni, Kristen; Reed, Sarah; Jiang, Hesheng; Jiang, Zongliang (Carl); and Tian, Xiuchun (Cindy), "Dosage Compensation and Gene Expression of the X Chromosome in Sheep" (2019). School of Natural Sciences Faculty Publications and Presentations. 37.
https://digitalcommons.csumb.edu/sns_fac/37
Comments
Copyright © 2019 by the Genetics Society of America doi: https://doi.org/10.1534/g3.118.200815
This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/ licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Supplemental material available at Figshare: https://doi.org/10.25387/g3.7221467.