How genetics explains the intelligence of parrots, the "humans" of the world of birds | Nature

Not anymore. A consortium of researchers from 11 Brazilian and North American institutions sequenced the genome of the species and discovered new genes and interactions, among others, responsible for these characteristics.

Sequencing is the result of a project called Sisbio-Aves, funded since 2012 by the National Council for Scientific and Technological Development (CNPq).

"It was created to help characterize the country's bird biodiversity," says Brazilian researcher Claudio Mello of the Department of Behavioral Neuroscience of the University of Health and Sciences of the United States. 39, Oregon in the United States. "The idea was to sequence the genomes of several Brazilian birds in order to unravel their genomes and try to better explain their characteristics."

According to researcher Patrícia Schneider, from the Federal University of Pará (UFPA), who also participated in the study, Sisbio-Aves focuses on species that answer crucial questions about phylogeny, evolution, population genetics, neuroscience and health. behavior. "Sequencing is a first step in answering these questions," he says.

Another member of the consortium, the geneticist Fabrício Santos, of the Federal University of Minas Gerais (UFMG), cites another goal of sequencing parrot DNA. "We wanted to have a map of the genes of this species and identify the differences in their evolution that could give us indications on the functioning of the brain (including the human brain) as well as the genes possibly badociated with longevity."

Like most vertebrates, the Amazon has about 25,000 genes. In some cognitive aspects, this species exceeds even primates, with the exception of the human being. "Perhaps the most striking example is what is called object permanence, that is, the ability of the animal to know that something that is presented to him before is always present, even if it is hidden, "says Mello.

"It's the game that puts something under a box, for example, and the animal knows where it's hidden." Parrots can solve this problem, but other animals, including monkeys, have more difficulty in losing their sight. "

For this work, the specimen that provided the DNA samples was a parrot named Moses, born in the early 2000s. to a biologist and now lives with the veterinarian of the city of Pitangui (MG), Brazil. Belo Horizonte 127 km.

"By comparing the genomes of other parrots and birds as humans, we were able to identify genes with marked differences indicating important functions in terms of longevity and cognitive processes related to the disease. vocal learning of the sequenced species, "says Santos.

According to Patrícia, sequencing has identified about 4,000 genes and shown the similarities of Amazona aestiva with other birds, but also what it has of different. "This research has led to the identification of genome modifications, that is, mutations of certain genes, as well as the identification of other proprietary modifications to the genes." Parrots that reinforce the idea that cognitive ability and longevity are unique attributes of this group of animals because they are absent in other species, "he says.

"Their more detailed study, mainly related to cognitive functions, can elucidate important questions because we observe many parallels between man and these birds."

Mello gives more details on the findings, clbadifying them into three main findings. "We found paralogous genes (a gene duplicated in a particular species or group) that seem to be specific to parrots," he says. "One of them is what is called the PLXNC1, involved in the formation of neuronal connections, that is, how an area of ​​the brain connects to other neurons. others to form neural circuits. "

According to the researcher, it was already known that this gene had a different regulation in the vocal region of birds and in the laryngeal cortex in humans. That is, he seems to be involved in regular speaking circuits in people and singing in birds. "The fact that it is partially duplicated in the Amazon indicates that there is increased regulation, which may explain the increase in their voice capacity," Mello said. "We have also discovered other duplications that have led to new genes only in parrots, but their functions are not yet clear."

A second discovery concerns longevity. Parrots and some other birds live much longer than expected by their weight. The life expectancy of Amazon aestiva, for example, is 2.5 to 3 times higher than it should be. Basically, it would be like a human being between 150 and 200 years old.

"We found that he and some other long-lived birds, compared to those who live less, are altering several genes that control processes such as aging and cell proliferation, repairing damage to DNA , tumorigenesis (origin of the tumor), protection against oxidative stress and the immune response, for example ", explains Mello. "This suggests that the sequenced species uses multiple pathways to have greater longevity."

The third finding concerns changes in the regulatory regions of several genes that control brain growth and cognitive abilities. They are similar to those seen in humans and distinguish humans from other primates, who have smaller brains and less cognitive ability.

"This shows that some mechanisms that have led to greater growth of the brain and intelligence in humans must also have acted in the same way in parrots," says Mello. "We consider them to be the most intelligent birds and, in this sense, they are like humans compared to other primates."