Fig. 5: Sex and population signatures in heavily fixed archival specimens.
From: Century-old chromatin architecture revealed in formalin-fixed vertebrates
In two species (mouse and water dragon), Pearson correlation-based analysis of genome-wide archival MNase occupancy signals resolves clusters of individuals by sex and population. PCA plots of principal components one and two (A) illustrate strong separation of females from males, while plotting components two and three (B) reveals clustering of individuals along PC2 in accordance with population. For mouse, only the autosomal chromosomes were considered for this analysis. The shape of individual PCA plot points indicates the specimen’s sex (F = star; M = triangle) and colour indicates the population (mouse—blue = laboratory, orange = wild; water dragon – blue = urban, orange = non-urban). Wild mice are labelled by collection location and water dragons are labelled by collection date. C Representing the Pearson correlation scores of the first two PCA axes as a heatmap, a relatively stronger differentiation of the sole female water dragon from the four males emerges in comparison to the sex-based differentiation observed in mouse. In the mouse heatmap, as in the PCA plots, the individuals cluster first by sex and then by population (L = lab; W = wild). Created with BioRender.com, released under a Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International license.
