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. Author manuscript; available in PMC: 2021 Oct 1.
Published in final edited form as: Nature. 2021 Mar 10;592(7852):80–85. doi: 10.1038/s41586-021-03345-1

Figure 3. Early embryonic genetic bottlenecks and their relationship to trisomic rescue.

Figure 3

(a) Schematic depicting the detection of the earliest post-zygotic mutations and the estimation of contribution to samples from their VAFs. (b) Hypothetical lineage tree of early embryo showing how measurements of VAF relate to cell divisions. (c) The contribution of the major lineage to the umbilical cord as calculated from the embryonic mutation with the highest VAF. (d) Early trees of trophoblast clusters of PD45566 and PD45567, with the contribution of lineages to the umbilical cord coloured in blue in pie charts. The umbilical cord exhibits an asymmetric contribution of the daughter cells of the zygote. (e) Early cellular contribution in PD45557 shows separation of one placental lineage. (f) In PD42138 and PD42142 the placental and umbilical cord lineages do not share any early embryonic mutations. (g) B-allele frequency (BAF) of germline SNPs on chromosome 10 in PD45581, showing a trisomy in PD45581c (placenta), but a disomy in PD45581e (placenta) and PD45581f (umbilical cord). SNPs absent from mother are coloured in blue. (h) Overview of genomic events in PD45581 and parents leading to the observed mosaic trisomic rescue. The arrowheads highlight areas of two genotypes in PD45581c due to meiotic recombination in the mother.