27 Mar 2015

The genetics of musical talent: an interview with Irma Järvelä

Would Mozart have become a great composer had his family not encouraged his musical career? Irma Järvelä is a clinical geneticist at the University of Helsinki, Finland, who investigates the molecular genetics of musical traits. After devoting 25 years of her career to the identification of genes and mutations involved in human diseases, she now works in close collaboration with bioinformaticians and music educators to study the influence of genes and the cultural environment in music perception and production. 

What got you interested in studying the genetics of musical talent?
Järvelä: We were studying a lot of things that affect human diseases and I found that it’s also important to understand how the human normal brain functions. This could be helpful to understand the diseases in more detail. In genetics we have genes and then we have environmental effects. […] Our genes do not always tolerate our environment—when you think of carcinogenics, for example—and this kind of crosstalk between genes and the environment is also present in music. […] I was interested in this interaction between the environment and studying music, or listening to music.

Your research shows that several genes involved in inner-ear development and auditory neurocognitive processes are linked to musical aptitude. Does this mean musical talent is innate?
Järvelä: Yes, our recent study points to the genes that are associated strongly with an innate, or inborn, musical aptitude. It was already known before that newborns are interested in very complex musical patterns already at the age of a couple of days, and from research studying human brain function in musicians and non musicians, there is evidence that music is a biological trait. In our study we identify the regions in the human genome that are strongly associated with the ability to perceive and listen to sounds and structures in music.

So do ‘musical geniuses’ really exist? Would Mozart have become a great composer if his family hadn’t encouraged his musical training?
Järvelä: Mozart is a typical example of a talented composer whose family was musical. There are a lot of families in our days that have several professional musicians, so part of the musical talent is explained by the genes but of course also to exposure to music. It’s like an allergy; the risk for an allergy is only expressed when the pollen is coming, so you need this environmental trigger. And music is an excellent environmental trigger. Children who have an ability for music have to be exposed to music, otherwise we don’t know whether they can become musicians. So a rich musical environment is of course needed.

Is it possible to compensate for the lack of genetic musical ability with musical training?
Järvelä: I think it can be compensated to some extended but never fully. […] Some researchers have claimed (and I agree) that children first of all inherit the ability to perceive music and hear music. And if the parents are also very musical and good teachers, that is the ideal setting for the transmission of both the genes and the perfect environment.

Are there also examples of musically talented people that don’t come from a family of musicians?
Järvelä: We have a couple of cases in our family collection, which consists of 800 people in Finland, where the parents are not very interested in music but the child is very talented. Also vice versa, we also have cases where the parents are professional musicians, but the children are not at all interested, or their musical scores are moderate or low.

How do you explain these exceptions?
Järvelä: I think it’s possible that these cases are explained by a novel mutation, because the human genome is supposed to have de novo mutations quite frequently. But we cannot say anything concerning just a couple of cases, this kind of studies are not reliable. We would need more cases.

In a recent study you show that listening to classical music affects gene expression in musically experienced, but not inexperienced, individuals. How do you explain this?
Järvelä: Yes, this is true. We had a group of participants who were professional musicians or experienced listeners [of classical music], and in the other group the participants told us they were not so interested in music. The participants were not informed which music they came to listen […]. Some people would come out and say “yeah, I know this music, this was nice”, and of course those who had no musical experience didn’t know what was played. […] If you think about it people always choose what they like. We saw an effect in people who knew the music, or who were used to listening to classical music.

Do you see this effect on gene expression with any type of music?
Järvelä: I don’t know because this is the first study and you have to start somewhere. This was with classical music but I agree that we should study other genres like jazz or hip hop, or whatever other type of music. I would suggest that jazz would be the next one because imagination, improvisation and creativity in jazz are more prominent and we might get some different effect. I think there might be shared effects and non-shared effects.

Have you thought of studying other ethnicities, maybe semi-isolated tribes, which have a completely different type of music and culture?
Järvelä: It would be nice but it’s easier said than done. I suspect they would have different genetic profiles because of the long distance in genetics, and also the cultural effects are different. It would be extremely interesting to compare these different natural surroundings and it might be that that is the most true effect of music. I think the basic similarities are there, because the human inner ear is very well conserved in evolution. 

What other questions would you like to address in the future?
Järvelä: We are currently studying the genes for creativity in music, and this will hopefully be published this year. This week we have just published a paper on the genetic profiles of professional musicians, just before and after they played a fabulous symphonette at a concert. […] Then we want to look at the different musical genres, and gene regulation and evolution of music.

Oikkonen J., P Onkamo, L Ukkola-Vuoti, P Raijas, K Karma, V J Vieland & I Järvelä (2014). A genome-wide linkage and association study of musical aptitude identifies loci containing genes related to inner ear development and neurocognitive functions, Molecular Psychiatry, 20 (2) 275-282. DOI: http://dx.doi.org/10.1038/mp.2014.8

Kanduri C., Minna Ahvenainen, Anju K. Philips, Liisa Ukkola-Vuoti, Harri Lähdesmäki & Irma Järvelä (2015). The effect of listening to music on human transcriptome, PeerJ, 3 e830. DOI: http://dx.doi.org/10.7717/peerj.830 

Kanduri C., Minna Ahvenainen, Anju K. Philips, Harri Lähdesmäki & Irma Järvelä (2015). The effect of music performance on the transcriptome of professional musicians, Scientific Reports, 5 9506. DOI: http://dx.doi.org/10.1038/srep09506

An edited version of this interview was published in Lab Times on the 27-03-2015. You can read it here.

17 Mar 2015

Hippos are (almost) definitely whales, not pigs

Hippos are strange mammals. They lack hairs and sweat glands, and have an unusually thick skin. The only other mammals that share these features with hippos are whales, but they look nothing alike, except they’re also huge and live in water. Coincidence?

Traditionally hippos were included in the Suidae (pigs) branch of the mammalian evolutionary tree, but molecular data unambiguously shows that they're closely related to cetaceans (whales, dolphins and porpoises). This not only sounds unlikely (hippos look much more like pigs than whales), but it's also quite difficult to testthere is simply not enough fossil evidenceSo the origin of hippos has remained something of a mystery. Now, a new fossil discovery by a team of French and Kenyan palaeontologists may have tipped the balance of the hippo evolutionary history.

Common hippo showing off its mandibles.
Fossils of hippo are rare. Every now and then a tooth pops up, but bones are nearly impossible to find. “To make a comparison between whales and hippos we need to find their ancestors. We had the whale ancestor but until now the hippo ancestor was unknown,” says Fabrice Lihoreau, a palaeontologist at the University of Montpellier, in France.

In 2005, Lihoreau and colleagues discovered a mandible with teeth of unusual morphology in the paleontological collection of the National Museum of Kenya, in Nairobi. Lihoreau is an expert on anthracotheres, a diverse group of semi-aquatic herbivorous mammals that lived in Africa from around two to 40 million years ago. For some time palaeontologists had suspected that anthracotheres could be the ancestor of hippos. “We published many studies suggesting hippo is related to anthracotheres, and not to pigs. This new discovery not only supports that, but it tells us precisely to which lineage of anthracotheres hippos originated from,” Lihoreau explains.

The newly found teeth have morphological features of both anthracotheres and hippos. They belonged to a large herbivorous mammal that thrived in Lokona, Kenya, around 28 million years ago. The discovery of this new hippo-like anthracothere, named Epirigenys lokonensis for ‘hippo’ (Epiri) and ‘origin’ (genys), shows that hippos are definitely not pigs—they originated from an old lineage of antrachotheres, the bothriodontines. And not only that, Lihoreau says, “we added a bit more to the history of mammals in saying that hippos are African, they were born in Africa.”

Evolutionary transition of the upper molar from an anthracothere (left),
Epirigenys (middle) and a primitive hippo (right). 
Many African mammals (rhinos, elephants, giraffes…) originated in Eurasia and then migrated to Africa in two large waves of migration, around 35 and 20 million years ago. Because the oldest fossils of a ‘true’ hippo are about 16 millions years old, palaeontologists have assumed they crossed into Africa on a land bridge during the second wave of migration. But Epirigenys lived 28 million years ago, so hippos must have originated from their anthracotheres ancestor in Africa. This also explains why fossils of hippo ancestors hadn’t been found before: palaeontologists were looking in the wrong place.

But are hippos whales? The discovery of Epirigenys doesn’t prove that hippos and whales came from the same ancestor, but it makes any different scenario rather unlikely. “This study is very important because now we have a hippo ancestor. And we know that the ancestors of hippos are from South-East Asia, and the ancestors of whales are also from South-East Asia, from the same period”, Lihoreau says.

Phylogenetic relationships between hippos, anthracotheres and cetaceans.
Lihoreau and colleagues are now going to focus on searching for the ancestor of anthracotheres in South-East Asia, to then compare it with the ancestor of whales, which is well known. If the team gets lucky, they might find their  holy grailthe common ancestor of hippos and whales.

Jonathan Geisler, a palaeontologist at the New York Institute of Technology who studies the evolution of dolphins and whales says “About 15 years ago there was a big gap between the age of the earliest hippos and the oldest whales. These authors, and their collaborators, have been steadily filling in this gap through the discovery of new fossils, as well as detailed studies that have moved known fossil species into this gap.”

Many questions remain unresolved. Lihoreau suspects that hippo ancestors hopped into Africa around 30 million years ago alone and… swimming. “This is somewhat speculative but certainly seems possible,” says Geisler. “There is evidence to suggest some anthracotheres were semi-aquatic, and were able to make this crossing.” This hypothesis implies that the hippo-whale ancestor already lacked hairs and sweat glands, which would have “constrained the evolution of the hippo group to get into water”, Lihoreau says. His team is going to collaborate with geologists and geochemists to try and figure out in what sort of environment hippo ancestors were living. This should help us understand what shaped the evolution of hippos towards their semi-aquatic lifestyle, which is very rarely seen for herbivorous mammals (capivaras and beavers are the only other exceptions).

Lihoreau F., Fredrick Kyalo Manthi & Stéphane Ducrocq (2015). Hippos stem from the longest sequence of terrestrial cetartiodactyl evolution in Africa, Nature Communications, 6 6264. DOI: http://dx.doi.org/10.1038/ncomms7264

An edited version of this article was published in Lab Times on the 17-03-2015. You can read it here.