UB participates in the sequencing of the genome of all birds around the world

The Bird 10,000 Genome Project (B10K), an international consortium to sequence the genomes of all birds around the world, sequenced the genomes of 363 bird species in the second phase of this micro-project, which began in 2015. This scientific milestone, published in the journal Nature, represents the largest complete genome dataset for eukaryotes sequenced in a biological group to date.

The study, sponsored by B10K, counts on the participation of over 150 researchers from 125 institutions in 24 countries. Among them are researchers Marta Riutort, Julio Rozas, Jacob González-Solís and Joan Ferrer Obiol, from the Faculty of Biology and the Research Institute on Biodiversity (IRBio) of the UB.

The article, published in the journal Nature, features 257 new bird genomes that expand the genetic material sequenced during the first phase and shed light on the evolution of genomic diversity among bird lineages. It is led by the University of Copenhagen (Denmark), the China National Genebank BGI-Shenzhen (China), the Chinese Academy of Sciences (China), the Smithsonian National Museum of Natural History and the Rockefeller University (United States). The study used for the first time a genome alignment method (Cactus) that does not require a reference genome and with which researchers could identify more than twice as many homologous genomic regions (a 149% increase in orthologous encoding). compared to previous studies.

The evolutionary history of birds

According to the findings, passerine birds – the order with the largest number of bird species – exhibit genomic characteristics that differ from other bird groups (for example, an additional copy of the growth hormone gene). Songbirds – the group with the most species within the Passerines – have also lost a gene called cornulin, which could contribute to the evolution of their large vocal repertoire.

“Compared to other groups of birds, Passerines, the order that includes species such as sparrows or goldfinches, have a higher content of guanine-cytosine nucleotide (GC) in the regions of the genome that code for proteins and use a lower percentage of synonymous codons “, observes the researcher Joan Ferrer-Obiol, of the Department of Genetics, Microbiology and Statistics of the UB.” In addition – he continues -, the Piciformes – a group including peaks -, have a greater number of transposons than the other orders of birds. Future studies will determine the biological and evolutionary importance of these results “.

Thanks to the large number of sequenced bird genomes, research has identified 10% more highly conserved nucleotides in DNA. “These hitherto unknown genetic compounds are found largely in regions of the genome that are not coding for proteins and which could have great functional importance, especially in gene regulation (such as IncRNA, untranslated exons or binding sites of transcription factors) “, emphasizes Professor Julio Rozas, member of the aforementioned department and of the Bioinformatics Barcelona (BIB) platform.

Genetic study facilitated the detection of changes caused by natural selection at a level of only one nucleotide AND. “This power of detection is only possible when species are strongly represented in comparative genomic analyzes,” notes Guojie Zhang, principal investigator at B10K and head of the Villum Center for Genomic Biodiversity at the University of Copenhagen. ‘These genomes allow us to explore genomic variations between different bird groups and help us understand their diversification processes.’

The genetic basis of Cory’s migratory behavior

The UB-IRBio research team focused on sequencing the genome of Cory’s shearwater (Calonectris borealis), a long-distance migratory species that has breeding colonies in the Canary Islands and spends the winter in places like the coasts of South Africa and Namibia. For more than fifteen years, the group led by Professor Jacob González-Solís has been studying the migratory behavior of the species through the use of motion monitoring devices (GPS).

In addition, the team is actively involved in one of the comparative genomics projects being conducted with the new genomes, which aims to identify specific regions of the genome associated with the migratory behavior of birds. In particular, it will look for the molecular footprint of evolutionary convergence by comparing the genomes of different groups of birds in which this behavior appears independently, “notes Professor Jacob González-Solís, of the UB’s Department of Evolutionary Biology, Ecology and Environmental Sciences.

“The B10K project is not finished yet,” notes Professor Marta Riutort, member of the UB’s Department of Genetics, Microbiology and Statistics. “We are still conducting many phylogenomic and comparative genomic analyzes which will provide new data on the evolutionary history of birds. Having all this genomic data and a phylogeny will allow researchers to conduct a large amount of studies, such as research on the genetic basis of migration. This knowledge will allow us to better understand how the morphological characters and genomes of birds have evolved, and others such as migration and social behavior ”.

Fieldwork and museums to preserve endangered biodiversity

Much of the genome sequencing relied on the analysis of tissue samples from museums, which allowed for the sequencing of the genome of rare birds and endangered species. Collaborating centers include the Smithsonian National Museum of Natural History, the Museum of Natural History of Denmark, the Louisiana State University Museum of Natural Science, and the National Museum of Natural Sciences (MNCN-CSIC).

For Carsten Rahbek, co-organizer of the B10K project and former bird curator at the Natural History Museum in Denmark, “this report is also proof of how science is advancing unpredictably over time. According to Peter Hosner, current bird curator at the Natural History Museum in Denmark, “the study shows how investing in basic field work provides value to research for decades, an important lesson at a time when nature is rapidly disappearing.

There are still big open questions about the evolutionary relationships of birds. “New genomes play a key role in understanding bird diversification,” said Josefin Stiller, an expert at the University of Copenhagen, who is leading efforts to build a new evolutionary tree for all bird families. Therefore, the new phase of the project has already begun, another scientific challenge to sequence genomes of species representing the 2,250 genera of birds. According to Erich Jarvis, principal co-researcher on the B10K project and a professor at Rockefeller University and the Howard Hughes Medical Institute, “being able to access all of the genetic diversity of birds will help us decipher the genetics of its various complex traits, such as flight, vocal learning and high density of brain neurons “.

Images: Jon Fjeldså