Understanding Epigenomics through monozygotic twins

http://biolecture.org/index.php/Sanzhar_Aitbay

 

Monozygotic twins are identical twins and form when a single fertilized egg splits. Depending on the timing of the spilt, thetwins will have different numbers of placentas (the organ that nourishes the fetus inside the womb) and amniotic sacs.

Wiki 

Twin studies are studies conducted on identical or fraternal twins. They reveal the importance of environmental and genetic influences for traits, phenotypes, and disorders. Twin research is considered a key tool in behavioral genetics and in content fields, from biology to psychology. Twin studies are part of the broader methodology used in behavior genetics, which uses all data that are genetically informative – siblings studies, adoption studies, pedigree, etc. These studies have been used to track traits ranging from personal behavior to the presentation of severe mental illnesses such as schizophrenia.

Twins are a valuable source for observation because they allow the study of environmental influence and varying genetic makeup: "identical" or monozygotic (MZ) twins share nearly 100% of their genes, which means that most differences between the twins (such as height, susceptibility to boredom, intelligence, depression, etc.) are due to experiences that one twin has but not the other twin.^[1]

Twins are also useful in showing the importance of the unique environment (specific to one twin or the other) when studying trait presentation. Changes in the unique environment can stem from an event or occurrence that has only affected one twin. This could range from a head injury or a birth defect that one twin has sustained while the other remains healthy.

Modern twin studies have concluded that almost all traits are in part influenced by genetic differences, with some characteristics showing a stronger influence (e.g. height), others an intermediate level (e.g. personality traits) and some more complex heritabilities, with evidence for different genes affecting different aspects of the trait — as in the case of autism.^[2] The methodological assumptions on which twin studies are based, however, have been criticized as untenable.^[3][4]

 

- The fact that monozygotic twins have 100% identical genomes was the primary reason that leads me to study this topic under the Epigenomics topic. This is interesting how we can observe the Epigenetic changes in twins with 100% match.