Published online by Cambridge University Press: 24 October 2012
The science of genetics is undergoing a paradigm shift. Recent discoveries, including the activity of retrotransposons, the extent of copy number variations, somatic and chromosomal mosaicism, and the nature of the epigenome as a regulator of DNA expressivity, are challenging a series of dogmas concerning the nature of the genome and the relationship between genotype and phenotype. According to three widely held dogmas, DNA is the unchanging template of heredity, is identical in all the cells and tissues of the body, and is the sole agent of inheritance. Rather than being an unchanging template, DNA appears subject to a good deal of environmentally induced change. Instead of identical DNA in all the cells of the body, somatic mosaicism appears to be the normal human condition. And DNA can no longer be considered the sole agent of inheritance. We now know that the epigenome, which regulates gene expressivity, can be inherited via the germline. These developments are particularly significant for behavior genetics for at least three reasons: First, epigenetic regulation, DNA variability, and somatic mosaicism appear to be particularly prevalent in the human brain and probably are involved in much of human behavior; second, they have important implications for the validity of heritability and gene association studies, the methodologies that largely define the discipline of behavior genetics; and third, they appear to play a critical role in development during the perinatal period and, in particular, in enabling phenotypic plasticity in offspring. I examine one of the central claims to emerge from the use of heritability studies in the behavioral sciences, the principle of minimal shared maternal effects, in light of the growing awareness that the maternal perinatal environment is a critical venue for the exercise of adaptive phenotypic plasticity. This consideration has important implications for both developmental and evolutionary biology.
Target article
Behavior genetics and postgenomics
Related commentaries (24)
A call for an expanded synthesis of developmental and evolutionary paradigms
A developmental science commentary on Charney's “Behavior genetics and postgenomics”
A straw man's neogenome
Affirmation of a developmental systems approach to genetics
Assumptions in studies of heritability and genotype–phenotype association
Biology trumps statistics in the postgenomic era
Clinicians learn less and less about more and more until they know nothing about everything; researchers learn more and more about less and less until they know everything about nothing: Discuss
Epigenetic regulation of brain-derived neurotrophic factor: Implications in neurodevelopment and behavior
Estimating the actual subject-specific genetic correlations in behavior genetics
From gene activity to behavior (and back again)
Gene-independent heritability of behavioural traits: Don't we also need to rethink the “environment”?
Genetic sensitivity to the environment, across lifetime
Heritability estimates in behavior genetics: Wasn't that station passed long ago?
Is behavioral genetics ‘too-big-to-know’ science?
Is genomics bad for you?
Neogenomic events challenge current models of heritability, neuronal plasticity dynamics, and machine learning
Non-Mendelian etiologic factors in neuropsychiatric illness: Pleiotropy, epigenetics, and convergence
Parental brain and socioeconomic epigenetic effects in human development
Postgenomics and genetic essentialism
Preventing a paradigm shift: A plea for the computational genome
Relational developmental systems: A paradigm for developmental science in the postgenomic era
The fate of heritability in the postgenomic era
The history of the nature/nurture issue
Twin and family studies are actually more important than ever
Author response
Humans, fruit flies, and automatons