Question

Explain how genetics and environment influence the similarities and differences within twins. Be sure to give specific examples alluding back to the textbook (as well as any other sources of information, such as research).

Answer 1

For nearly all human traits, both the genetics and environmental influence together in different ways. The mechanism that causes one trait to be influenced more than by genetics than environment and the vice-versa is difficult to untangle.

For example, there is a great evidence that says that the identical twins tend to be more similar in height than fraternal twins. Although identical twins and fraternal twins are raised in relatively same environment, it shows that the genetics factors have lot more control on height than environmental factors.

Where as if you consider the immigrants, the US born Asian immigrants child is much taller than their parents when he/she grow up. This suggests that environmental factors dominate over genetics in height.

However a recent study (The Journal of Nuclear Medicine) says that it found evidence that genetic influence on cerebral glucose metabolism played a major role in bilateral parietal lobes (right and left) and the left temporal lobe of human brain, while environmental factors influence is dominating in other regions.

A study published in May 2015 ( Nature Genetics ) examined more than 14.5 million pairs of twins for more than half a century and concluded that the Nature vs Nurture debate is draw.

Still research is going on regarding the influence of genetics and environment on the brain. Researchers say that if they are able to distinguish the influence of genetics and the environment on the Brain, then the answer to question (Nature vs Nurture) would be answered.