Lately, there has been a planetary activity in my thoughts about bronze age collapse of various civilizations of the known world. This thought forced me to burden myself with the complex Indic arguments that usually a technical person should be away from. Complex and interesting as the arguments were, I went for marathon reading till I stumbled upon seemingly a simple question: “WHO WE ARE AND HOW WE GOT HERE?”.
As I moved forward with my material, I started to think that I shouldn’t have burdened my complex Indic mind with this. Little did I know that there are people who would love to answer such questions and even have written a scientific book on the same. David Reich, Geneticist of impeccable record, is one such person who took burden of answering the stated question.
My question or David’s question has not come for the first time. This question is archaic in nature. Alice Robert’s of the world, Jared Diamonds, Siddhartha Mukherjee’s of the world have tried to provide answer to this seemingly non-complex paradigm. Many have proposed migration theories trying to address these questions. Once a newbie into this, now, after reading through their work- I have become biggest fan of this conundrum. It has been 1 month now, the likes of David Reich and Tony Josephs have been debating in my mind with the likes of Raj Vedam and Shrikant Talageri.
There has been so many cluttering and decluttering sessions that have occupied my mind space. The worst or best part of being in such state is that you yourself start becoming part of argumentative mind. The whole conundrum is an interesting thought process. Answering or decluttering what was supposed to have happened by a hypothesis is interesting. Proposing hypothesis is itself a daunting task and proving it without any opposition is next to impossible in these kind of studies.
Between all these archaic debates and conundrum, my damidic GIS mind set its sight on our bread and butter question i.e. how maps/GIS/geo-informatics will be helpful in decluttering the debate. Initially, I was sceptic of finding any scientific process/method/field that will link map with my question. To my surprise, I stumbled upon an entire science to address this genre of questions. In 19th century, scientific world called this as Bio-Geography. I was quite happy to see geography and where there is geography, there will always be maps. With this clear idea of bio-geography, I ventured into complex interdisciplinary area which led me to first geology, then paleogeography, followed to paleo ecology and finally population genetics. Combine bits of these, you will get exposed to a very interesting but lesser known branch of science called “Phylogeography”.
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Tongue Twister ‘Phylogeography’
Phylogeography is branch of sciences that tries to answer the following or one of the following questions
- How species responded to past historic events?
- What drives phenomenon of historical assemblage, divergence and specialization?
- What ‘s insight in origin and maintenance of regional/global biodiversity patterns?
- Why and how speciation might have happened?
Phylogeography as such is fairly new subject. But this has touched all species, even humans. In human context, it had tried to answer some of the long standing questions/topics/theories like
- Human dispersal
- Interaction of Neanderthals, Deisovan with modern humans
- Out of Africa theory (modern human migration theory)
- Ancient Human DNA and great migrations of Pre-Bronze age.
- Out of India and Aryan migration theory etc.
Phylogeography has also been used by researchers in field of virology, paleo biology, paleoecology, history and anthropology. Phylogeography helps to reconstruct phylogenesis and test evolutionary hypothesis in viruses, animal and bird species as well. Phylogeography also identifying geographically structured genetic signals that are present within and among species.
Why Phylogeography now?
Development and adaptation of a technology is a slow and organic process. Certain factors accelerate the phenomenon and certain others deaccelerate the phenomenon. I have mapped 4 factors that have contributed over the decade for slow but study adaptation of this field to uncover mysteries that glared us.
- Growth of high computational hardware systems
- Increased accuracy in modelling
- Reduced cost in genome sequencing
- Growth in GIS technology
1 or combination of some or all, have contributed to demystifying some of the cases. To take one example, there are models like BEAST which uses modern technology and computation power to give phylogenesis of the virus/animals from their sequenced genomes. Output (in kml files) of these is also spatially enabled, which is basically geographic spread model. BEAST Model and KML based maps have been integrated in software. Best output example of these is: the study of Phylogeography of Ebola presented on website virological.org and in one of github repository by Andrew Rambut.
Nextstrain website also gives some of the best example including COVID-19 also known as “SARS-CoV-2”. Nextstrain displays examples that have integration of Phylogeny and Maps. Figure 2 show the snap shot of the genomic analysis of corona virus. This analysis is time and space enabled. For more details, please visit Nextstrain website (https://nextstrain.org/).
Other popular but not know example of Phylogeography is map output of geneticist David Reich on ancient DNA and their links to present human population and their migration. His map is a cluster compression of huge research on genetics and how various groups of humans or different cultures interacted. His researche records time and place of supposed interaction of Pre-Bronze age world. His maps have opened renewed debate in the world of archeology on human migration especially with respect to Indo-European Bronze age migration and how it shaped the world including Indian sub-continent. I will not go into the details of the study but you can read his book “WHO WE ARE AND HOW WE GOT HERE” or refer derived articles.
Future is ‘Embedded’
Maps are crucial in decluttering and making sense of hypothesis and assumptions in phylogeography. There is an entire science of modelling -paleo climate and paleo ecology – waiting to be discovered on maps. Imagine a situation where you know how paleo climate at various geographical location was and how ecosystem worked in such geography on maps. What today’s satellite maps show is just glimpse of present day phenomenon but if we were to come up with map or image of historic past, say Bronze Age, there will be a lot of decluttering in the philosophical world related to human evolution. We would be able to tell how and why we humans migrated and how and when mixing happened and how we have come to this stage where we are now.
For me, Phylogeography has its rebirth in work of David Reich and likes of him. As a branch of science, it could offer bright future for the integration of genetics, maps and modelling. Maps would be integral but embedded part of such science and hence will indirectly support some of the rarest of rare branches which would help humans in their quest of knowledge and discovery.
