:strip_icc()/i.s3.glbimg.com/v1/AUTH_59edd422c0c84a879bd37670ae4f538a/internal_photos/bs/2018/5/V/1bIl5ARea6B32rqsK7lA/foto-1-oceanologa-maira-proietti-comecou-a-estudar-tartarugas-marinhas-em-2004.jpg)
[ad_1]
Sea turtles are not animals as faithful as they thought. They can "betray" their places of birth and spawning (not always returning to the same, as is generally believed), their partners and even their species.
At least two genetic studies of populations of these reptiles from different parts of the world, including Brazil, carried out by two Brazilian researchers, from the federal universities of. Rio Grande do Sul.
The geneticist Sarah Vargas, from UFES, began her studies on sea turtles in 2005, when she began her Ph.D. at the Federal University of Minas Gerais (UFMG).
"I have worked with the five species present in Brazil, but mainly in leatherback turtles (Dermochelys coriacea) and deer (Eretmochelys imbricata), two endangered species," he says. "I studied samples from Brazil and the Indo-Pacific, but I used published genetic sequences from around the world."
Her most important research began in 2008, when she spent six months in the Nancy FitzSimmons Nature Conservation Laboratory, at the University of Canberra, Australia, where she organized and processed 492 DNA samples of turtle-headed combs.
"They had already been collected by other researchers working with Nancy in 13 spawning grounds in the Pacific and the Indian Ocean, located in Saudi Arabia, in the Chagos Archipelago, Australia, in the Solomon Islands, Seychelles, Iran and Malaysia, "said Sarah.
of the National Council for Scientific and Technological Development (CNPq), she returned to Australia to badyze the data in the laboratory of Professor Simon Ho de University of Sydney.
"With these works, we seek to genetically characterize populations that have never have been studied with this approach, "explains Sarah.
"It is important to understand the migratory routes of turtles, which can be born on a spawning beach in an ocean, but migrate thousands of miles and feed elsewhere."
Among the findings, it is possible that animals originating in the Indian Ocean arrive in food producing areas in Brazil, such as Fernando de Noronha and Atol das Rocas. "We also found that the degree of filopathy of female turtles is variable," he says.
This word, from ancient Greek, means "love of the home" and defines the behavior of certain species of animals in order to always return to specific places to feed or procreate.
It was almost a certainty for sea turtles. The results of Sarah's research, however, reversed this dogma. They showed that there is a genetic mix of maternal lineages with distinct origins and that the separation of populations is more complex than previously thought.
This means that they do not always return and all on the beach where they were born to breed. Or there would be no new nesting sites.
"This may be the only explanation for the colonization of other places, or they would all be badociated with a single nesting beach, and we know that this is not what is happening . "
A study conducted by a geneticist revealed a high rate of multiple sea turtles in Brazil – Photo: Divulgação
More recently, as part of a pioneering work in Brazil, Sarah studied the multiple authorship of sea turtles in the country. As males are rarely found, as they do not leave the oceans, unlike females during the spawning period, most surveys use samples of them for badyzes of the biology of the species.
"Thus, one way to obtain information about humans is to use the genetic information of the females and their respective pups to infer data of the size of the male population," says Sarah.
The data has not been published yet. "But the work suggests that the breeding population of Turtlehead Turtles (Caretta caretta) on the beach of Povoação, in the Linhares District, in the state of Espirito Santo, appears to be composed of: about two men for each woman, "says Sarah.
"The multiple paternity rate, meanwhile, was about 50%, with a contribution of up to three males for each nest." In other words, half of the litters have more than one parent. In other words, half of the females have puppies of three different parents.
Oceanologist Maira Carneiro Proietti, of the FURG Oceanographic Institute, began studying sea turtles a year before Sarah, in 2004, still in third year of the Oceanology course.
"Júlia Reisser and I have today created a project to study people living in the Arvoredo Marine Biological Reserve in Santa Catarina," he recalls. "We love these animals, they have fascinated me and I continue to search for them."
Since then, Maira has studied several species of different places.
"In my Ph.D., I studied turtles along the Brazilian coast, especially in isolated sites such as the São Pedro Archipelago and São Paulo and the Abrolhos National Marine Park", he explains.
"In my laboratory, we also study turtle-headed turtles and olive turtles (Lepidochelys olivacea) off the Rio Grande do Sul.The goal is to understand their biology and ecology."
One of Maira's main research focuses on the genetic characterization of immature populations of several species, in order to understand the diversity and connectivity that unites them, as well as to those living in other parts of the world, to help preserve these animals.
In addition to verifying and understanding the genetic diversity of populations and of places of origin, spawning and feeding, the work resulted in a surprising result.
"We have identified young turtles, still puppies, in feeding areas located along the Brazilian coast, resulting from crosses between different species that breed on the coast, "says Maira.
"Up to now, we have observed animals resulting from hybridization between the turtle comb and the bighead comb, the comb and the olive, the green and the headstrong and the morbid and olive. "
According to the researcher, before these revelations, hybrid turtles had only been reported in spawning grounds. She says that young hybrids appear to have characteristic distribution patterns, different from those of adults.
"For example, the results of crossing cabeçuda with comb turtles were found in greater numbers in Praia do Cbadino, in the far south of Brazil, which is a known foraging place for the first, but where the second is commonly produced, "says Maira.
In general, taking into account all species, not just hybrids, the work of scientist FURG shows that the origins of sea turtles found on the country's coasts are much more diverse than we thought previously, with high contributions also regions of West Africa and the Caribbean, in addition to the island of Trindade in Brazil.
Source link
