Complex sentence: The effects of parental care on the HPA and ACTH resulted from epigenetic changes, whereby high licking-grooming led to decreased DNA methylation that allowed for increased access to the hippocampal glucocorticoid receptor genes in the offspring.
Split into simpler sentences: The effects of parental care on the HPA and ACTH resulted from epigenetic changes, whereby high licking-grooming led to decreased DNA methylation. In turn decreased methylation allowed for increased access to the hippocampal glucocorticoid receptor genes in the offspring.