Читать книгу Abnormal Psychology - William J. Ray - Страница 101

Mitochondria are structures within a cell that are involved in the production of energy. It is assumed that mitochondria descended from bacteria that began to live inside single-celled organisms more than a billion years ago. As such, mitochondria have their own DNA (see next paragraph), which contains 13 coding genes with about 16,000 base pairs. Thus, a given cell in your body contains both the nuclear DNA and mitochondria and their DNA.

What is interesting is that generally mitochondrial DNA (mtDNA) is inherited only from the mother, clearly a violation of Mendelian inheritance. Because mtDNA does not recombine sections of DNA from the mother and father, it is very stable and mutates slowly. This gives mtDNA a special application in the study of evolution. It has helped researchers to discover the genetic link in certain disorders that show maternal or mitochondrial inheritance patterns, such as Leber’s hereditary optic neuropathy, a disorder that results in rapid loss of vision beginning in adolescence.

mitochondrial DNA (mtDNA): deoxyribonucleic acid (DNA) of mitochondria structures within a cell; because mtDNA does not recombine sections of DNA from the mother and father, it is very stable and mutates slowly

mitochondrial inheritance: generally mitochondrial DNA (mtDNA) is inherited only from the mother. mtDNA is contained within each cell and is related to energy production

Evidence is also accumulating that mitochondrial dysfunction is involved in specific mental disorders (Regenold et al., 2009; Rossignol & Frye, 2012). This is referred to as the mitochondrial dysfunction hypothesis. Mitochondrial dysfunction has been identified using a number of different techniques. One technique is to identify structural changes in mitochondria. A second is to examine the manner in which the mitochondrially related genes produce proteins. A third is the use of metabolic studies. Since mitochondria are involved with energy production, it is possible to measure glucose concentration in cerebrospinal fluid. These studies have shown differences in mitochondrial functioning in individuals with bipolar disorder, schizophrenia, and autism spectrum disorders as compared to healthy controls.