Fig. 4

Haplarithmisis unveils GW mosaicism following multipolar zygotic division. A Three chronological time-lapse images of E07 (initiation of the cleavage furrow, the ongoing first division and the embryo immediately after cleavage and before cell isolation of the cleaving zygote). B A visual interpretation of the haplarithm profiles (Additional file 2: Fig. S2, B) for the biparental diploid (B1), the diandric triploid (B2), and the androgenetic blastomere (B3) of E07. For each blastomere from top to bottom, respectively, we depict the area and copy number inherited from paternal homolog 1 (H1, light blue) or paternal homolog 2 (H2, dark blue), together forming the paternal haplotype and the area and copy number inherited from maternal homolog 1 (H1, red) or maternal homolog 2 (H2, pink), together forming the maternal haplotype. Shifts from H1 to H2 represent recombination sites. Simultaneous presence of H1 and H2 represent regions of heterodisomy. In E07, a distinct recombination profile of the inherited paternal haplotype is retrieved in the biparental diploid (black arrows) and the androgenetic blastomere (green arrows) and a combination thereof is retrieved in the diandric triploid cell, pointing towards dispermic fertilization. Given the presence of a common paternal genome in B1 and B3, segregation from a common paternal pronucleus is implied, assuming one paternal copy to be present in B3. However, copy number is not represented in uniparental blastomeres since the value is normalized to a relative value of two in the absence of chromosomal errors or a second parental genotype. C Schematic representation of the suggested mechanistic origin of blastomeres in E07, including replication and pronuclear apposition of the parental genomes and karyokinesis by a tripolar spindle leading to a multipolar division of the zygote. D Schematic representation of possible events leading to the segregation of a zygote in a biparental diploid, a diandric triploid, and an androgenetic cell lineage in two other embryos. Curved arrows depict replication of the genome