The Iberian lynx has increased its genetic diversity thanks to mixing with the boreal lynx

2024-01-15 18:01:36

Updated Monday, January 15, 2024 – 17:01

The sequencing of the complete genome of the Iberian lynx (Lynx pardinus), published in 2016, provided a valuable tool to researchers working on the conservation of this animal, emblematic of the peninsular fauna. In parallel to the efforts to increase the population of the fluid, experts point out that ensuring genetic variety is essential so that the species can adapt to changes in the environment, consolidate its reproductive capacity or increase the chances of surviving diseases.

This Monday, a new study led by researchers from the Doana Biological Station provides new information about the genetic past of the species. The work indicates that the genetic diversity of current Iberian lynxes is greater than that which the species had thousands of years ago. Researchers believe that genetic admixture with its closest relative, the common lynx (Lynx lynx, also called boreal or Eurasian), contributed to the greater genetic variation of the modern Iberian lynx, despite the reduction in population in recent centuries.

It is estimated that Thousands of years ago, the distribution of the Iberian lynx extended to southern France and Italy. The boreal lynx, for its part, came to inhabit the north of the peninsula until recently, creating opportunities for genetic exchange between the two species. This flow would have spread over the years to modern populations.

“Analyses have revealed that modern lynxes share more genetic material with their sister species, the Eurasian lynx, than older lynxes. This suggests that “There would have been a genetic exchange between the two species during the last two millennia.”summarizes researcher Mara Lucena, first author of the study published in the journal Nature Ecology & Evolution, who developed this work during her doctoral thesis in Doana.

The analysis is based on the sequencing the genomes of three ancient Iberian lynxes from fossil bone samples (dated approximately between 2,000 and 4,000 years ago): one from Andjar from around 4,300 years ago, another from Alcanar in Tarragona from 2,500 years ago and another from Algarve in Portugal, dated approximately 2,100 years ago. Afterwards, They compared these genomes with the data available from 30 current specimenswith a boreal lynx that lived approximately 2,500 years ago, from the north of the peninsula, and with 12 modern boreal lynxes from six different populations.

“The samples were provided by paleontologists who work in each of these sites,” explains José Antonio Godoy, researcher at the Doana Biological Station. “They are part of a set of 58 samples already analyzed in a previous work, in which data was obtained from hundreds of historical samples and ten ancient samples, but only from the mitochondrial genome, which is more abundant and relatively easier to obtain. To this new work, we tried again with 20 of the most promising available samples and managed to recover nuclear genome data from three. They are not many, but they provide the first and very valuable insight into nuclear genetic variation in the Iberian lynx in a remote past, approximately 2000-4000 years ago.”

Population “bottlenecks”

The Iberian lynx diverged from its close relative, the boreal lynx, approximately one million years ago., although their genomes reveal subsequent DNA transfer between both species. Since separating from the lineage, the species has gone through four population “bottlenecks” that left its numbers at a hundred specimens in two nuclei at the beginning of this century. The first came with its isolation on the Peninsula and with causes related to climatic variations; the second, 300 years ago, when their numbers fell until there were only about 1,5000 individuals; the last one already in the 20th century due to epidemics among rabbits, hunting and the destruction of their natural habitat.

Despite the successes in its recovery during recent decades, the Iberian lynx has not yet reached a population that ensures its genetic viability for the future. Experts estimate that at least 1,100 reproductive females are needed, when 326 were counted in the 2022 census. That is why it remains essential to increase the number of subpopulations and promote connectivity between them for genetic exchange. Objective pursued by the LIFE-Lynxconnect project, financed by the European Commission.

In this context, The paper’s findings could have implications for future conservation strategies. In particular, the hypothesis of a genetic crossing with a different population, a strategy to restore genetic diversity and reduce inbreeding. Under normal conditions it is not recommended, since the offspring would have a lower probability of survival and reproduction and therefore the viability of the population would decrease. However, the authors believe that in the case of the lynx it could be applicable if a population crisis occurs.

“The possibility of genetic management based on hybridization with a closely related species could be considered an option of last resort. to restore the lost diversity, especially in a case like that of the lynx in which we know that hybridization has already occurred in the past and that it will possibly occur in the future if the distributions overlap again,” explains José Antonio Godoy. “It is not something that we propose that needs to be done now. Fortunately, the species is recovering dramatically and the goal is to get populations large enough to ensure long-term genetic and demographic viability.”