Genetics and the Past

Genetics is a science that is in early stages compared to other sciences, such as biology or chemistry. A lot is still to be explored; however, genetics can also make connections to the past. For example, it has been a common belief that the isthmus of Panama was formed anywhere approximately three million years ago. Research has recently emerged suggesting that the connection between North and South America emerged four to eight million years ago.

Eciton army ants are a type of ant that can only travel on dry ground, due to their lack of wings. The study was conducted by sequencing DNA from different ants from Brazil to southern Mexico. This was done across nine different species of Eciton army ants.  The similarities in their DNA sequencing proves that the ants crosses the region earlier than originally thought. This evidence was found by Moreau, an associate curator at the Field Museum in Chicago, by complete accident. The study was originally conducted to understand the diversity of army ants. 

There is also geologic evidence that complements the evidence found by Moreau. Montes, a geologist of the University of the Andes in Bogota, Colombia. He has found the isthmus emerged around the same time by dating uranium preserved in rocks surrounding the connection.

Although it is thought that genetics helps us understand the future, like possible diseases and mutations, it can also help us understand the past, when combined with other research.

Ant Genome Provides Evidence that Could Rewrite the History of Panama Land Bridge

It is an accepted fact that the land bridge that connects North and South America formed around 3 million years ago due to a collision of tectonic plates. However, new evidence suggests that this might not be the case, and instead the bridge actually formed much earlier, around 4-8 million years ago.  The spark of this geological controversy being nothing other than  research on the evolutionary and population genetics of Eciton army ants.

The study on the ants was conducted by Corrie Moreau, who was looking into the diversity present among the different ant species. She conducted her research by analyzing different DNA samples of the ants from each of the 9 species through a technique known as genotyping. This allowed Moreau to compare the genetic variation between ants belonging to different species, as well as individuals belonging to the same species. The genomic data suggests that the ants crossed over from South America to North America far earlier than 3 million years. The ants don't have wings, so in order for this to be possible they would need to have traveled the distance on dry  land.

This doesn’t mean for certain that the ants crossed over by means of a land bridge though, as they could have floated across the water on a tree branch or other form of debris. However, other geologic and biological data also support the idea that the Panama land bridge formed earlier than 3 million years ago. Such evidence includes fossilized teeth belonging to ancient primates that suggests they traveled across continents far earlier than 3 million years ago.

Although nothing concrete can be determined from this study as of yet it is interesting to see how genetic research is applicable across many different fields. It just goes to show that you never know where research will take you. You start out looking into the diversity of ants and end up in a major geological controversy.

http://www.nature.com/news/ant-genomes-rewrite-history-of-panama-land-bridge-1.20924

http://onlinelibrary.wiley.com/doi/10.1111/mec.13846/abstract;jsessionid=3FB002C162ECC42154EC9C9E88DD3F95.f04t04