Fig. 1From: Placental mitochondrial DNA content is associated with childhood intelligenceCorrelation between intra-pair difference in mitochondrial DNA content in placental tissue and intra-pair differences in total, verbal and performance IQ in dizygotic (n = 102), monozygotic-dichorionic (n = 34) and monozygotic-monochorionic twin pairs (n = 38)Back to article page