Summaries: the best scientific articles for nature and environmental sciences summarized

Preface

DNA methylation is an epigenetic process in which a methyl group is added to a histone within the DNA molecule. This changes the structure of the DNA, creating tissue-specific DNA methylation patterns. DNA methylation plays a crucial role in determining tissue-specific patterns of gene expression.

DNA methylation in the face of dynamic environments

The fact that DNA methylation plays an important role in the specification of specific cell type programs, implies that DNA methylation is preserved during the lifetime of the tissue. Because of this, it is assumed

Summary with the article: Epigenetics: Stress makes its molecular mark - Nestler (2012)

Some people who are exposed to stress are more vulnerable to negative outcomes than others. Differences in epigenetics may explain this vulnerability. Epigenetic mechanisms provide short and long-term responses to stress.

Aggressive mice

When a person is stressed, gene expressions in areas the brain will be activated or inhibited. Many stress-induced changes are adaptive, but some are also harmful and can be permanent. Research has been done using mice which were exposed to other, aggressive mice. After ten days of this experiment, the mice started to avoid these other mice. They also became less interested, less adventurous and more likely to be obese. These symptoms could last for months and could be treated with antidepressants. It turned out that mice that had been given cocaine a week before being exposed to aggressive mice had more stress-related

Evolution refers to the process of change in gene frequencies within populations over many generations. The major principle of evolution is reproductive fitness, which refers to the likelihood that an individual will produce offspring or that that individual’s offspring will produce offspring. Evolution provides an explanation for how a mechanism developed but also why it developed. Previously adaptive mechanisms may not be adaptive anymore in modern society.

Evolutionary developmental psychology refers to a field which looks at development of humans from an evolutionary perspective. It is useful to look at which cognitive operations underlie adaptive behaviour. Psychological mechanisms (e.g. cognitive psychology) may be the missing link between evolution and behaviour.

It is possible that domain-specific mechanisms designed by natural selection to deal with specific aspects of the physical or social environment (e.g. face recognition) evolved. However, evolution has also influenced domain-general mechanisms (e.g. executive