Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Frequent flyers, bottle gourds crossed the ocean many times

19.02.2014
Bottle gourds traveled the Atlantic Ocean from Africa and were likely domesticated many times in various parts of the New World, according to a team of scientists who studied bottle gourd genetics to show they have an African, not Asian ancestry.

"Beginning in the 1950s we thought that bottle gourds floated across the ocean from Africa," said Logan Kistler, post-doctoral researcher in anthropology, Penn State. "However, a 2005 genetic study of gourds suggested an Asian origin."

Domesticated bottle gourds are ubiquitous around the world in tropical and temperate areas because, while they are edible when young, the mature fruit make ideal lightweight, waterproof, liquid-carrying vessels. They were popular in areas either before development of ceramics or where ceramics never developed.

The 2005 study looked only at targeted sequence markers that turned out not to be informative on the population level, said Kistler. Now we can do sequencing of the large single copy area of the plastid genome, which is about 86,000 base pairs of DNA, he added.

Unlike animals, which have two types of DNA -- nuclear and mitochondrial -- plant cells have three types of DNA -- nuclear, mitochondrial and plastid. Animal mitochondrial DNA is often used in genetic studies because it is completely inherited from the mother and changes very slowly, but in plants, mitochondrial DNA is prone to structural rearrangements, while often carrying a slow mutation rate. The DNA found in plastids such as the organelles that perform photosynthesis and create starch or pigments, is a better choice for plants because it does not recombine, but it mutates fast enough for population-level studies.

The researchers, who report their results in a recent issue of the Proceedings of the National Academy of Sciences, looked at 36 modern samples of bottle gourd and 9 ancient samples. They found that all the ancient bottle gourds from the Americas that were tested fell within the normal variation of the African bottle gourds and not the Asian bottle gourds.

"The best explanation for this is that they came directly from Africa," said Kistler. "However, we wanted to test the possibility that gourds did float from Africa to form New World populations."

Previous studies found that gourds do float in the oceans and that after long periods of time in the ocean they still have viable seeds. The researchers developed an ocean-current drift model that showed that wild African gourds could have simply floated across the Atlantic during the Late Pleistocene. They suggest that large mammals like the mammoth helped naturalized populations establish in the neotropics, because these large mammals were known to eat various members of the family that includes gourds. The seeds are found in ancient deposits of large mammal dung.

Bottle gourds in Africa exist today mostly in the domesticated form, with only small populations of the wild variety in Kenya and Zimbabwe. In the ocean drift model, the researchers looked at realistic, unrealistically conservative and optimistic scenarios. They divided the western coast of Africa by latitude and simulated 12 years of gourd release where one gourd per month entered the ocean in each latitude division. The shortest amount of time it took for a gourd to arrive was 100 days, with an average arrival time of about nine months.

According to the researchers, it is feasible that gourds did float across the Atlantic Ocean frequently. This is especially true of gourds growing near rivers that flow into the ocean.

"It wasn't one gourd that came over and gave rise to all New World gourds," said Kistler. "Populations show up in Florida and Mexico around 10,000 years ago and in Central America a little later."

Also working on this project were Álvaro Montenegro, assistant professor or geography, Ohio State University; Bruce D. Smith, curator of North American archaeology, Smithsonian Institution; John A. Gifford, associate professor of marine affairs and policy; Richard E. Green, assistant professor of biomolecular engineering, University of California Santa Cruz; and Lee A. Newsome, associate professor of archaeological anthropology, Penn State.

The National Science Foundation partially supported this work.

A'ndrea Elyse Messer | EurekAlert!
Further information:
http://www.psu.edu

More articles from Agricultural and Forestry Science:

nachricht Six-legged livestock -- sustainable food production
11.05.2017 | Faculty of Science - University of Copenhagen

nachricht Elephant Herpes: Super-Shedders Endanger Young Animals
04.05.2017 | Universität Zürich

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

Im Focus: Bacteria harness the lotus effect to protect themselves

Biofilms: Researchers find the causes of water-repelling properties

Dental plaque and the viscous brown slime in drainpipes are two familiar examples of bacterial biofilms. Removing such bacterial depositions from surfaces is...

Im Focus: Hydrogen Bonds Directly Detected for the First Time

For the first time, scientists have succeeded in studying the strength of hydrogen bonds in a single molecule using an atomic force microscope. Researchers from the University of Basel’s Swiss Nanoscience Institute network have reported the results in the journal Science Advances.

Hydrogen is the most common element in the universe and is an integral part of almost all organic compounds. Molecules and sections of macromolecules are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

Innovation 4.0: Shaping a humane fourth industrial revolution

17.05.2017 | Event News

Media accreditation opens for historic year at European Health Forum Gastein

16.05.2017 | Event News

 
Latest News

New approach to revolutionize the production of molecular hydrogen

22.05.2017 | Materials Sciences

Scientists enlist engineered protein to battle the MERS virus

22.05.2017 | Life Sciences

Experts explain origins of topographic relief on Earth, Mars and Titan

22.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>