Q: Answer this scientifically and in a non-ideologue manner: are there any ethnicities that are genetically more aggressive than other ethnicities?
Krishna: Although some studies showed genetic basis for violence (1, 2, 3, 4), mostly through hormone regulation, it probably is unrealistic to think that a couple of genes by themselves could code for violence or crime.
Genes involved in neurotransmission, such as those related to acetylcholine (Ach), nitric oxide (NO) and GABA, have also been found associated with aggression (3).
Based on a large number of twin and sibling studies that span almost four decades, the genetic contribution to delinquency is thought to be approximately 50%. The current model is that environmental influences account for the other 50% of cases of violent behavior and delinquency (2).
Age differences, gender differences too influence aggressive behaviours (3).
Cultural differences could also affect the results obtained in association studies. Violence and criminality indexes show differences worldwide and can be influenced by laws, economy, moral and ethics. (3).
Regarding genome‐wide studies, although none of them achieved genome‐wide significance, they have been helpful in highlighting potential risk genes and pathways involved in neurodevelopmental processes, such as neuron projection and synaptic plasticity, not previously considered in candidate gene studies. This may indicate that aggressive behaviors do not only involve neurotransmitters or hormonal functions, but also molecules involved in establishing neuronal circuits, neuron‐to‐neuron connectivity and brain plasticity. Signaling pathways seem to play an important role in these processes, such as those involved in the control of synaptic and neuronal function, as well as hormonal signaling.
To date, results obtained from association studies should be taken with caution since some results are conflicting and are often performed in underpowered samples. Future studies should be performed in larger samples, use homogeneous phenotypes and standardized measurements, also combined with neuroimaging data, to identify genes that underlie aggressive behaviors in humans.(3)
Sometimes epigenetic factors too influence aggressive behaviours (5).
Individuals differ genetically in any given ethnicity. So everybody having the same genetic background for aggression is not possible. Some epigenetic factors like suppression, ill-treatment might trigger aggression but these things don't influence all the individuals in a society in the same way.
With so many factors controlling the behaviours of human beings, it is highly unlikely that 'ethnicity' can be marked as the cause for aggression in the scientific world.
So, the answer is most probably, 'no'.