ISIS Press Release 14/01/09
New research on maternal care puts the environment and epigenetic potential at centre stage of how organisms shape their lives and the lives of their offspring
Dr. Mae-Wan Ho
Neither genetic nor environmental determinism rules
Is it our genetic makeup or the environment that determines who we are? Startling new research results on how maternal care has lasting influence in the offspring’s behaviour that perpetuates for generations [1] are saying that’s not even the right question to ask.
Evidence has been emerging since the early 1990s that lack of parental care or childhood abuse can contribute to subsequent criminal behaviour [2]. A study sponsored by the US National Institute of Justice showed that a child who experienced neglect or physical abuse was 53 percent more likely to be arrested as a juvenile and 38 percent more as an adult compared with a child who was not neglected or abused. Another study found that 68.4 percent of male inmates from a New York State correctional institution reported childhood abuse or neglect: 71.2 percent for violent offenders and 61.8 percent for non-violent offenders.
It has been estimated that up to 70 percent of abusive parents were themselves abused [3, 4], and 20 to 30 percent of abused infants are likely to become abusers. These findings in humans are replicated in experiments on primates [1].
Clearly, the environment plays a large role, but it does not absolutely determine whether children will grow up to be criminals, any more than their genetic makeup determines what they will become. More importantly, changing the environment can often undo the harm that individuals, or their parents, have experienced in early life, as we shall see.
Myth of genetic determinism perpetrated in academia
Mainstream genetics research during the decades since the discovery of the DNA double helix in 1953 has focussed on identifying ‘genes’ or ‘genetic predisposition’ for every ‘trait’, real or imaginary [5] (see Living with the Fluid Genome, ISIS publication). Imaginary traits are rife in the hybrid discipline of ‘evolutionary psychology’, long dedicated to inventing stories on ‘selective advantage’ for each of the ‘traits’ so that the corresponding gene could become ‘fixed’ in the population by neo-Darwinian natural selection.
Another hybrid discipline ‘behavioural genetics’, formerly dedicated to studies based on identical twins, began identifying DNA (gene) markers for behaviour; and indeed claimed to have found one for increased tendency towards violent behaviour in boys who experienced maltreatment in childhood [6]. The gene encoding the enzyme monoamine oxidase A (MAOA) – involved in the metabolism of neurotransmitters - exists in two variants, one expressing high activity, the other, low activity. While all boys in the study showed increased “disposition towards violence” if they received maltreatment as children, those with low enzyme activity appeared to show a greater increase. The researchers claimed a weak residual effect due to the low activity MAOA, while conceding the large effect of the environment. But even this weak genetic predisposition soon faded away as more data became available [7].
Behavioural geneticists are not the only ones wasting time and resources chasing ‘will o’ the wisp’ gene markers. The project to map genetic predisposition to diseases was the main rationale for the $3 billion Human Genome Project that decades later, delivered next to nothing; basically because it is not genomic DNA but epigenetic environmental influences that overwhelmingly affect our health and well- being [8] (see From Genomics to Epigenomics SiS 41).
Read the rest of this article here
http://www.i-sis.org.uk/caringMothersGeneticDeterminism.php
This is the second article in a six part series entitled Epigenetics and Beyond
The complete series is as follows:
Epigenetic Inheritance - What Genes Remember
http://www.i-sis.org.uk/epigeneticInheritance.php
Caring mothers strike fatal blow against genetic determinism
http://www.i-sis.org.uk/caringMothersGeneticDeterminism.php
From Genomics to Epigenomics Epigenetic Toxicology Rewriting the Genetic Text in Brain Development and Evolution Epigenetic Inheritance through Sperm Cells, the Lamarckian Dimension in Evolution
http://freepage.twoday.net/search?q=Mae-Wan+Ho
