Scientists compiling genetic catalog of Galapagos species

26 August 2021
Elias L. Benarroch

Galapagos Islands, Ecuador, Aug 26 (EFE) – A group of Ecuadorian and foreign scientists is hard at work on a project to decipher the genetic catalog of the Galapagos islands by comparing “the barcodes of life” of species in the archipelago with the world gene bank and hoping to discover new species.

The project – being mounted by the Galapagos Sciences Center (GSC) and the University of San Francisco of Quito (USFQ) with the support of the University of Exeter – for the past year has been collecting samples of soil and water containing the DNA of land and marine species to make an inventory of the flora and fauna of the volcanic islands.

They do that by extracting the so-called “barcodes of life” from the species that leave their DNA – along with assorted microorganisms – in the samples collected.

“The ‘barcode’ is a little piece of the whole genome, the same in all individuals and species, (and is used) to be able to compare them,” Diego Ortiz, an ecology and molecular biology researcher with USFQ and the technical coordinator of the “Galapagos Barcode” project, told EFE.

Made up of hundreds of “letters,” sometimes more than 1,000, this genetic sequence allows scientists to distinguish known from unknown species, determine whether they are endemic or invasive and how they differ from their counterparts or similar species elsewhere in the world.

By academic convention, and depending on the study group, the gene selected as the molecular markers in a given study is usually the same. For example, it is sequence “12-S” in fish and “16-S” in bacteria.

Preliminary analysis in the study revealed that there is greater diversity in the western portion of the archipelago than in the eastern islands, that is “30 to 40 percent were (fish) species that were not represented in the world (gene) sequence data banks,” said Diana Pazmiño, the co-chief researcher for the project with a Ph.D. in Marine Sciences.

This could be due to the fact that they are species new to science or that they are already known but “no genetic work has ever been done on them before,” she said.

With the university located on a beach where seals coexist with humans, its work now consists of reviewing “one by one” these sequences and determining how many are new and how many are not.

Located about 1,000 kilometers (620 miles) west of the Ecuadorian mainland, the Galapagos consist of 13 big islands, nine medium islands and 107 islets, and in this Marine Preserve, the world’s second largest, are sharks of different species, whales, sea turtles, rays, penguins and marine iguanas.

On land, the Galapagos are famous for their giant tortoises, finches and albatrosses, but the explosion and diversity of animal and plant life here has no parallel anywhere else in the world.

The incredible biodiversity within the archipelago helped scientist Charles Darwin to develop his Theory of Evolution, and in 1978 UNESCO declared the islands to be a World Heritage Site.

The collection of genetic samples is based on a “citizen science” initiative in which 74 Galapagos residents periodically go out to collect samples of soil and water from different islands and send them to the university laboratories on the islands of Santa Cruz, Isabela and San Cristobal.

The project also serves to help the collectors out economically amid the paralysis of tourism due to the coronavirus pandemic and also to raise the awareness of society in general about the environment.

At the labs, the samples are put through a careful process for extracting the DNA to determine, through molecular analysis, the genetic sequences of every living thing that left its genetic trace there, thus allowing scientists to create a “biological inventory” of the sample.

Ortiz said that in every cubic centimeter of mud or water, there can be millions of cells to separate and analyze.

“Depending on the type of sample, the process could take a couple of hours, or perhaps a whole day, which even so is a record because before we used to be talking about weeks,” Pazmiño emphasized regarding the capabilities of the new equipment and procedures being used on the islands with the three MinION gene sequencing machines.

The cells in the samples always come from existing plant and animal life, Ortiz said, that deposited them there very recently, given that DNA deteriorates and is undetectable within just a few hours after being separated from the original organism.

The research focuses on the microbiome of plants, insects, bony fishes, cartilaginous fishes, mollusks, freshwater invertebrates, reptiles, tortoises and marine mammals.

Read the original coverage from EFEvia La Prensa Latina at https://www.laprensalatina.com/scientists-compiling-genetic-catalog-of-galapagos-species/


Informing and sharing news on marine life, flora, fauna and conservation in the Galápagos Islands since 2017
© SOS Galápagos, 2021

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