Navigation Links
CU study relies on twins and their parents to understand height-IQ connection
Date:8/27/2013

The fact that taller people also tend to be slightly smarter is due in roughly equal parts to two phenomenathe same genes affect both traits and taller people are more likely than average to mate with smarter people and vice versaaccording to a study led by the University of Colorado Boulder.

The study did not find that environmental factors contributed to the connection between being taller and being smarter, both traits that people tend to find attractive.

The modest correlation between height and IQ has been documented in multiple studies stretching back to the 1970s. But the reasons for the relationship between the two traits has not been well understood.

The technique developed by the researchers at CU-Boulder to tease out those reasons may open the door for scientists to better understand why other sexually selected traitscharacteristics that individuals find desirable in matestend to be linked. People who are attractive because of one trait tend to have other attractive traits as well.

"Not just in humans but also in animals, you see that traits that are sexually attractive tend to be correlated," said Matthew Keller, assistant professor of psychology and neuroscience at CU-Boulder and lead author of the study appearing in the journal PLOS Genetics. "So if you have animals that are high on one sexually selected trait they are often high on other ones, too. And the question has always been, 'What's the cause of that?' And it has always been very difficult to tease apart the two potential genetic reasons that those could be related."

The key to the technique developed by Keller, also a fellow at CU-Boulder's Institute for Behavioral Genetics, and his colleagues is using data collected about fraternal twins, identical twins and, importantly, their parents.

It has been common in the past to use information about identical twins and fraternal twins to determine whether a particular trait is inherited, caused by environmental factors or affected by some combination of both. This kind of twin study assumes that each twin grows up with the same environmental factors as his or her sibling.

If a trait that's present in one twin is just as often present in the other regardless of whether the twins are fraternal or identical then the trait is likely caused by environmental conditions. On the other hand, if a trait is generally found in both identical twins but only in one of a set of fraternal twins, it's likely that the trait is inherited, since identical twins have the same genetic material but fraternal twins do not.

Similar studies also can be done for linked traits, such as height and IQ. But while scientists could determine that a pair of traits is passed down genetically, they could not further resolve whether inherited traits were linked due to the same genes influencing both traits, called "pleiotropy," or because people who have those traits are more likely to mate with each other, known as "assortative mating."

The new CU-Boulder study solves this problem by including the parents of twins in its analysis. While this has occasionally been done in the past for single traits, information on parents has not previously been used to shed light on why two traits are genetically correlated. In part, that's because existing twin registries, where information for heritability studies is drawn, don't often contain information on the parents.

Additionally, creating the computer programs that are necessary to crunch the data for multiple traits from twins and their parents in order to understand environmental effects and both types of genetic effects is difficult.

"These designs have never taken off because they're very difficult to code," Keller said. "It's a challenge. They're very complicated models."

For this study, the research team used data collected from 7,905 individuals including twins and their parents by the Colorado Twin Registry at CU-Boulder and the Queensland Twin Registry at the Queensland Institute of Medical Research in Australia.

Keller and his colleagues found that for the twins in their study, the correlation between height and IQ was not impacted by environmental conditions. Though Keller cautions that in societies where there is more nutritional variation among families, environmental factors could come into play.

The research team found that pleiotropy and assortative mating were about equally responsible for the genetic connection between height and IQ.

"It does look like there are genes that influence both height and IQ," Keller said. "At the same time, it also looks like people who are taller are slightly more likely to choose mates who are smarter and vice versa. Such mate choice causes 'IQ genes' and 'tall genes' to become statistically associated with one another. There are a lot of exceptions, but there's a statistical relationship that does happen more than would be expected by chance."

Now that the CU-Boulder team has built a computer model that is capable of disentangling the causes for linked traits, Keller said he hopes twin registries will begin to collect more data from parents and that other people in the field take advantage of the model.


'/>"/>

Contact: Matthew Keller
mathew.c.keller@colorado.edu
303-735-5376
University of Colorado at Boulder
Source:Eurekalert

Related biology news :

1. Study by UC Santa Barbara researchers suggests that bacteria communicate by touch
2. Law that regulates shark fishery is too liberal: UBC study
3. New study will help protect vulnerable birds from impacts of climate change
4. Study jointly led by UCSB researcher supports theory of extraterrestrial impact
5. BYU study: Using a gun in bear encounters doesnt make you safer
6. 15-year study: When it comes to creating wetlands, Mother Nature is in charge
7. Pycnogenol (French maritime pine bark extract) shown to improve menopause symptoms in new study
8. Crystal structure of archael chromatin clarified in new study
9. EU-funded study underlines importance of Congo Basin for global climate and biodiversity
10. University of Houston study shows BP oil spill hurt marshes, but recovery possible
11. Study demonstrates cells can acquire new functions through transcriptional regulatory network
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/15/2016)... June 15, 2016 Transparency ... titled "Gesture Recognition Market by Application Market - Global Industry Analysis ... 2024". According to the report, the  global gesture recognition ... 2015 and is estimated to grow at a ... by 2024.  Increasing application of gesture ...
(Date:6/9/2016)... TURKU, Finland , June 9, 2016 ... French National Police deploy Teleste,s video security solution to ensure ... France during the major tournament ... and data communications systems and services, announced today that its ... Police Prefecture to back up public safety across ...
(Date:6/3/2016)... 2016 Das DOTM ... Nepal hat ein 44 Millionen ... Kennzeichen, einschließlich Personalisierung, Registrierung und IT-Infrastruktur, an ... und Implementierung von Identitätsmanagementlösungen. Zahlreiche renommierte internationale ... teilgenommen, aber Decatur wurde als konformste und ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... MA (PRWEB) , ... June 23, 2016 , ... ... Peel Plate® YM (Yeast and Mold) microbial test has received AOAC Research Institute ... platform of microbial tests introduced last year,” stated Bob Salter, Vice President of ...
(Date:6/23/2016)... -- The Biodesign Challenge (BDC), a university competition that asks ... systems and biotechnology, announced its winning teams at the ... York City . The teams, chosen ... MoMA,s Celeste Bartos Theater during the daylong summit. Keynote ... of architecture and design, and Suzanne Lee , ...
(Date:6/23/2016)... ... , ... Supplyframe, the Industry Network for electronics hardware design ... Located in Pasadena, Calif., the Design Lab’s mission is to bring together inventors ... and brought to market. , The Design Lab is Supplyframe’s physical representation of ...
(Date:6/23/2016)... ... June 23, 2016 , ... In a new case report ... detail how a patient who developed lymphedema after being treated for breast cancer benefitted ... change the paradigm for dealing with this debilitating, frequent side effect of cancer treatment. ...
Breaking Biology Technology: