Epigenetics

For decades, the scientific community’s view of heredity has been written in the language of DNA. Deoxyribonucleic acid (DNA) is the genetic material of all living organisms. DNA is made up of two strands consisting of building blocks called nucleotides. Nucleotides are made up of the sugar deoxyribose, a phosphate group, and a base. The four bases of DNA are adenine, guanine, cytosine, and thymine. The nucleotides present in the chains are arranged in an elegant double helical structure. This structure is quite dynamic and has the ability to tip, buckle, roll, tilt, stretch, shear, and shift.

Gregor Mendel, the father of modern genetics, described genes as factors. Genes are scientifically defined as specific sequences of nucleotides and are generally the sequences used to describe the traits that are passed on from parent to offspring. Mendel’s scientific accomplishments lead him to conclude that inherited characteristics are determined by genes and that each organism contains two copies of each gene (one inherited from its mother and one from its father). Alternative versions of genes called alleles account for variations in inherited characters.
Although recombinations and genetic mutations have driven how phenotypic traits are passed on from one generation to another, recent discoveries associated with the field of epigenetics are changing the way researchers view heredity. Epigenetics is the study of heritable changes in gene function that occur without a change in the genetic sequence. Epigenetic theory relies heavily on gene activation and inactivation by way of mechanisms such as DNA methylation, histone acetylation, and RNA interference. Recent research suggests these epigenetic mechanisms are more than just “small players” in phenotypic transmission and development. Epigenetics may provide ways to connect past and future generations that, at one time, were never thought possible. This theory proposes the environment and experiences one’s ancestors were exposed to can have a great affect on one’s mental and physiological health. Epigenetics can change the way we think about our relationship with every generation.

Epigenetics certainly opens a wide array of questions related to developmental psychology. With respect to the “nature” aspect of development, the once semi-clear picture of an individual’s inherited characteristics is now blurred by the concept of genes’ ability to turn “on” and “off” at different points throughout childhood and adulthood. Below are links to an awesome PBS video describing epigenetic theory.

Ghost in Your Genes
Part 1
http://www.youtube.com/watch?v=GOid4jrCeFE
Part 2
http://www.youtube.com/watch?v=tg_XpenoBaM