Every gene in (almost) every cell of the body is present in two variants -- so called alleles: one is deriving from the mother, the other one from the father. In most cases both alleles are active and transcribed by the cells into an RNA message. However, for a few genes, only one allele is expressed, while the other one is silenced. The decision whether the maternal or the paternal version is shut down occurs early in embryonic development -- one reason, why for long it was thought that the pattern of active alleles is nearly homogeneous in the various tissues of the organism.
The new study (DOI:10.7554/eLife.25125), where CeMM PhD Student Daniel Andergassen is first author (now a PostDoc at Harvard University), uncovers a different picture. By performing the first comprehensive analysis of all active alleles in 23 different tissues and developmental stages of mice, the team of scientists revealed that each tissue showed a specific distribution of active alleles.
https://www.sciencedaily.com/...ses/2017/08/170818092138.htm