403V Poster Online - Virtual Posters
Tuesday June 07, 11:00 AM - 3:00 PM

Authors:
Kathie Sun; Oreper Daniel; Schoenrock Sarah; McMullan Rachel; Giusti-Rodriguez Paola; Zhabotynsky Vasyl; Miller Darla; Tarantino Lisa; Pardo-Manuel de Villena Fernando; William Valdar

Affiliation: University of North Carolina at Chapel Hill

Keywords:
Complex traits

Female mammals are functional mosaics of their parental X-linked gene expression due to X chromosome inactivation (XCI). This process inactivates one copy of the X chromosome in each cell during embryogenesis and that state is maintained clonally through mitosis. In mice, the choice of which parental X chromosome remains active is determined by the X chromosome controlling element (Xce), which has been mapped to a 176-kb candidate interval. A series of functional Xce alleles has been characterized or inferred for classical inbred strains based on biased, or skewed, inactivation of the parental X chromosomes in crosses between strains. To further explore the function structure basis and location of the Xce, we measured allele-specific expression of X-linked genes in a large population of F1 females generated from Collaborative Cross (CC) strains. Using published sequence data and applying a Bayesian "Pólya urn" model of XCI skew, we report two major findings: 1) inter-individual variability in XCI suggests mouse epiblasts contain on average 20-30 cells contributing to brain. 2) CC founder strain NOD/ShiLtJ has a novel and unique functional allele that is the weakest in the Xce allelic series, likely the product of copy number variation in the region. In this talk, we will focus on finding (1), illustrating how X-inactivation patterns in adult mice can reveal retrospective properties of the day 5 embryo.