Figure 4.

No asymmetric transcriptome sorting between 3-cell embryo sister blastomeres. (A) Asymmetric maternal transcriptome inheritance may persist through the early zygote (ez) and not be detected until the first (upper) or second mitotic division. Polarity determinants marking two lineages are shown as pink or blue. Asymmetry detection (boxed) is possible after first (upper) or second mitoses. First (a) and second (b and β) mitotic products are shown; ap, asymmetry plane. (B) Three-cell embryo (top) blastomere separation (Hofmann) showing zona removal (centre) and separated blastomeres <15 min after 2-cell → 3-cell division. Bar=50 μm. (C) Clustering analysis. Red line displays separation strengths (y axis) of a clustering using the top N separating transcripts (x axis). Grey background shading indicates the distribution of matching random separation strengths. (D) Comparative qPCR analysis of 3-cell blastomeres for transcripts as per Figure 1B. The value for one of the second mitotic blastomeres (b, labelled as per (A) and (B)) is set at 1.0, shown relative to values for the first mitotic (2-cell) blastomere (a) and the sister second mitotic blastomere (β).