Amadeus Mozart and Ludwig van Beethoven may be the most genetically studied musicians of all time. Why is that? Because their music is famous and loved? Because their personal history is full of celebrity and drama? Or are they just favorites of geneticists?
The narrative in most of the published studies is to understand the interaction between musical sounds and humans. I'm still not sure if this can be completely solved because music is more than just sound. It is a musical 'language', with or without words, that interacts with with the human mind and body. However, because we are a curious species, we seek to learn about those connections. And, as I suspect, the two famous composers have had a growing foundation of research on which to build upon.
A recent study* explores if genetic factors can determine extraordinary musical achievements. If that is so, then how do genes contribute or determine a person's musicality? This isn't a new query; geneticists have examined similar questions by studying the two famous composers for decades. However, recent advancements in molecular genetics allow scientists to probe deeper into human DNA, sometimes restudying old questions or asking new ones, especially of long-dead people.
Then again, when studying humans, sometimes these newer studies only confirm older results.
“An analysis of the famous composer's genetic make-up has revealed that DNA data has so far been too imprecise in capturing a person's abilities.”
In this recent study, an international team of researchers analyzed Beethoven’s DNA to investigate if and how any differences in his genes may account for his celebrated musical exceptionalism.
The deeper question is, how much can genes impact human traits, especially behavior? When considering a bird or a lizard, probably quite a bit. But humans are “messy.” There is no single quantitative or qualitative line that divides genetically determined and learned human behavior. This is the age-old “nature versus nurture” dilemma. The lines are fuzzy.
Ludwig van Beethoven was born in Bonn (a major city in Germany), which was at that time the capital of the Electorate of Cologne and partly dominated by Roman archbishops. He moved to Vienna (1792), Austria, to flee a dysfunctional family and meet other musicians.
During this time in history Napoleon restructured France (1789) and regions north including Bonn (1794) and Vienna (1805) after the famous French revolution. Beethoven supported Napoleon's reformations and composed his famous third symphony naming it “Napoleon”. After Napoleon proclaimed himself Emperor (1804) Beethoven rescinded the Napoleon dedication and renamed it “Eroica”. He even refused to play this symphony in front of French soldiers.
Beethoven lived during a tumultuous era of wars and conflicts with rulers. It was the rise of the German Enlightenment period, transition from the Classical to Romantic era in art and music, almost constant family turmoil, and loss of hearing. He was a man full of emotion, conviction, and righteousness. As his music conveys, he was a man with passion. Are there genes for that?
The researchers analyzed DNA sequences available from an earlier study (2023) in which the composer’s DNA was extracted from strands of Beethoven's hair. The authors then developed a ‘polygenic score’, a number that summarizes the estimated effect of many genetic variants on an individual's trait or behavior.
"Our aim was to use this polygenic score as an example of the challenges of making genetic predictions for an individual that lived over 200 years ago.”
They chose a specific component of music that had a score for “beat synchronization ability”, which is closely related to musicality. Beat perception and synchronization in humans is the degree to which an individual can synchronize their movements in time with a musical beat. In humans, it is commonly within 120 to 140 beats/minute and is frequently used in music composition. Ironically, beat synchronization was thought to be uncommon in non-human species and the mechanism determining the optimal tempo are unclear.
Although this was thought to be a human rhythm trait, a study in rats (2022) revealed that rats also showed head movements and neural recordings within the same range as humans. This suggests that "the optimal tempo for beat synchronization is determined by the time constant of neural dynamics conserved across species".
And Beethoven?
"The study found that Beethoven had an unremarkable polygenic score for general musicality compared to population samples from the Karolinska Institute, Sweden, and Vanderbilt University, USA. However, considering the limitations of the current polygenic scores and the fact that a genetic indicator for ‘beat synchronization ability’ may not directly tap into Beethoven’s composer skills (musical creativity), this finding is not unexpected.”
The genetic architecture of this trait is highly polygenic, meaning that it is influenced by many genes in the human genome. Authors identified 69 separate locations on the genome in which different genetic alleles (every person has two copies of a gene; they are called 'alleles') in the population account for some of the variability in how accurately people synchronize to a musical beat.
Genes associated with beat synchronization are more likely to be genes involved in central nervous system function, including genes expressed in brain tissue and genes involved in early brain development. Recent studies also found that beat synchronization shares some of its genetic architecture with other traits, including several that are involved in biological rhythms (walking, breathing, and circadian rhythm).
The polygenic score computes the sum of genetic effects associated with beat synchronization in each individual, but they are only a rough guess. It can tell us only what an individual’s likelihood of specific levels of beat synchronization would be in relation to the population-based model, but they do not correspond directly to an exact match with the person’s beat synchronization accuracy. Thus a person's beat synchronization may be a point amongst many in a wide area under the curve. And Beethoven's score may be lower than expected, but did that negatively impact his compositions?
“Although Beethoven had a rather low genetic predisposition for beat synchronization highlights the limitations of polygenic score predictions at the individual level. While polygenic score prediction is expected to get more accurate in the future, it is important to remember that complex human traits, including musical skills, are not determined solely by genes or the environment but rather shaped by their complex interplay.”
In conclusion the authors stated that the current study "only shows that we’ve been able to use genetics to explain a portion of the variability in beat synchronization skills (again, at the level of pooled data in a large study sample)."
When scientists talk about “heritability” they are referring to the amount of phenotypic variance explained by genetic variation. This does not mean that rhythm is only “genetic” versus only “environmental,” or that rhythm is genetic in certain people but not others.
"Scientifically we really can’t say for sure how and why an individual reaches (or does not reach) a certain level of musicality. So it’s not “either-or” but “both-and” genes and environment, and the incredibly complex biological interrelationships that occur during human development of musicality will take many, many more years of work to unravel!"
No comments:
Post a Comment