In the current issue of The Journal of Politics, Fowler and Dawes identify particular variants of the MAOA and 5HTT genes, both of which are part of the biological pathway that influences mood, emotion and judgment, as being “significantly associated with the decision to vote.”

Based on the description above, it’s easy to see how the serotonin pathway can affect social behaviors. Serotonin is a chemical in the brain that can induce feelings of happiness. Studies have shown that MAOA and 5HTT have different functions on the pathway, and variants of each gene have been linked to particular behaviors.

For example, the version of 5HTT with a slightly shorter genetic sequence has been associated with producing low levels of serotonin. Studies indicate that the “short” version of the gene has been linked to conditions such as alcohol dependence and bipolar depression.

On the other hand, the “long” version has been linked to more positive traits such as longevity and competitiveness in athletes.

Similarly, MAOA has high- and low-activity versions. The high-activity version has been linked with restless legs syndrome while the low-activity version, which is also associated with producing low serotonin levels, has been linked to increased sleep apnea and more severe symptoms of autism.

Because the “long” version of 5HTT and the “high” version of MAOA have been correlated with social behaviors, Fowler and Dawes proposed these as candidate genes for voting participation. They then looked at population data from the National Longitudinal Study of Adolescent Health to find confirmation of their theory.

Known as Add Health, the study itself consists of data collected from more than 15,000 young adults who the researchers tracked for seven years between 1994 and 2001. Among the questions the now 18-26 year-old participants answered for the researchers toward the end of the study were how often they’d attended church services in the past year and whether or not they voted in the 2000 presidential election.

Fowler and Dawes based their conclusions on the data collected from a subset of 2,300 Add Health participants because information for six genetic markers, including 5HTT and MAOA, were also collected from them. They correlated the genetic information with the answers from the surveys to find out if their candidate genes would turn out to play a role in voter turnout.

Turns out they found a couple of links. “Having a high MAOA allele,” Fowler and Dawes wrote in their paper, “raises the likelihood of voting by about 5%. Among people active in their religious organizations, having a long 5HTT allele raises the likelihood of voting by about 10%.”

Given the age range of the study participants, and the timing, it’s worth asking some questions about these conclusions. Fowler and Dawes themselves note that the young adults might have been voting for the first time during the 2000 election; the historic significance of that contest might have been a motivator along with theoretically being genetically inclined towards pro-social behavior. Having older participants in the study might have been able to provide the researchers with a more constant voting behavior perspective.

What Fowler and Dawes don’t discuss, though, is the role of religion during the 2000 election. One study published last year found that 25 percent of the public said their voting decisions for the 2000 election were influenced by the religious media. Another study found that members of evangelical Protestant churches form tight social networks that promote civic involvement such as political participation within these communities.

In short, the correlation between the long 5HTT version, religious involvement and voting might be a little more complicated than Fowler and Dawes contend.

ShareThis

In a recent paper, Southern California researchers announced that political involvement has a genetic component. Though they stopped short of identifying a gene or genes at work, the researchers concluded that the decision to go out and vote was genetically determined by up to 50 percent. Genes, they also noted, were partially involved in other activities such as attending rallies, donating to a campaign, and even running for office.

UC San Diego professor James Fowler and his colleagues published their results in The American Political Science Review – not your typical genetics journal. They studied 396 same-sex twins, culled from a list of nearly four million registered voters in Los Angeles County, who had voted in eight state elections between 2000 and 2005. They then replicated their results using an independent twin population taken from the National Longitudinal Study of Adolescent Health.  Aside from finding identical twins more likely to vote the same way than fraternal twins, their data also suggested that genetics accounts for 53 percent of variance in going out to vote.

Fowler and his colleagues aren’t the only ones who use twin studies for their research. In a way, twins can provide researchers with perfectly matched test subjects and controls. Because identical twins have the same genetic information, for example, scientists can do one-on-one comparisons to find out why one is left-handed and the other right-handed, or why one has cancer but the other doesn’t. Such twin studies allow researchers to estimate how much of behavior is due to genes and how much can be attributed to environmental factors. They can also make such comparisons over larger groups of twins to look for a gene or genes that could explain these common traits.

Twin studies have indicated a genetic component underlying an amazing variety of traits, including:

• age-related hearing loss;
• neophobia, or aversion to new food;
• back pain;
• chronic fatigue syndrome;
• heart disease;
• nearsightedness;
• obsessive-compulsive disorder;
• the size of one’s brain; and,
• happiness.

But not all researchers are impressed.

“We suggest that no scientific purpose is served by the flood of heritability estimates generated by these studies,” psychologist Leon J. Kamin and economist Arthur S. Goldberger wrote in a 2002 paper.

Kamin and Goldberger looked at two population samples used as the basis for several twin studies. One twin population known as MISTRA (Minnesota Study of Twins Reared Apart) is composed of identical twins separated early in life. Researchers wishing to study behavioral differences who used this group might think that any similarities between the twins would be genetic (attributed to nature) and any differences would then be due to environmental influences (nurture). However, Kamin and Goldberger found some cases where statements the twins had given indicated they might have compared notes prior to being interviewed. Such interactions, they argued, could skew the results in studies using MISTRA twins.

A second twin population is known as SATSA (Swedish Adoption/Twin Study of Aging). This sample is composed of four groups of twins: identical twins separated in childhood; identical twins reared together; fraternal twins separated before the age of 11; and fraternal twins reared together.

Kamin and Goldberger questioned the definition of separation as in some cases the twins were raised within the same extended family though they didn’t live in the same house. The environmental influences would be too similar, they argued, and that again could skew any conclusions reached by those conducting studies using these twin populations.

One twin study where researchers seem to have been able to successfully separate and track twins and multiples for years was conducted between 1953 and 1997. Known as the Child Development Center’s Study of Twins Reared Apart, the data are part of the records donated by lead researcher Peter Neubauer to Yale University, with the stipulation that the information remain sealed until 2066. For those unwilling to wait, some tidbits may be gleaned from a book by two of the study’s unknowing participants, Elyse Schein and Paula Bernstein, in their book Identical Strangers, as well as in Neubauer’s own book, Nature’s Thumbprint.

ShareThis