Unveiling Complete Genome Sequences of Six Ape Species

An international research collaboration has unveiled complete genome sequences for six ape species, revealing greater genetic differences among these species, including humans, than previously understood. This groundbreaking study was conducted by teams from Pennsylvania State University, the National Human Genome Research Institute (NHGRI), and the University of Washington.

The newly established reference genomes are comprehensive sequences that represent the full genetic makeup of each species. This advancement allows for enhanced comparisons across species, facilitating the identification of DNA variations that may influence health and survival. Previously, assembling complete DNA sequences from each chromosome was hindered by technological limitations.

The findings, published in the journal Nature, provide significant insights into primate evolution and highlight novel, species-specific genes as well as genes with multiple copies. These discoveries indicate adaptive genetic signatures associated with diet, immune responses, and cellular functions, which are critical in understanding the evolutionary pressures that shape the genomes of great apes.

Researchers have noted that the newly sequenced genomes are more accurate and complete than earlier versions, offering deeper insights into genetic functions and disease mechanisms. This includes the potential identification of genes and variants that are important for health. The insights gained from these reference genomes are expected to advance conservation genetics for endangered species, as well as enhance understanding of human evolution and health.

One of the lead researchers emphasized that this achievement marks a significant milestone in comparative genomics, enabling a comprehensive appreciation of genome evolution that was not possible with incomplete genomic data. The human genome was first sequenced in 2001, and sequencing apes has been a long-standing goal in the field as it provides context for the evolutionary history of the human genome.

Using advanced sequencing techniques and computational algorithms, the research team successfully decoded the genomes of six ape species: chimpanzee, bonobo, gorilla, Bornean orangutan, Sumatran orangutan, and siamang. This process involved long-read sequencing technologies that allowed for uninterrupted reading of long DNA segments, resulting in complete genome assemblies without gaps.

The research uncovered new genes and multi-copy gene families that may partially explain the observed differences among species, including human-specific traits such as cognitive abilities. Additionally, the team identified unique evolutionary markers, enhancing the ability to compare closely related species and analyze previously inaccessible regions of the genome, which are rich in sequences that form non-canonical DNA.

Non-canonical DNA structures do not conform to the standard double-helix arrangement and may play critical roles in regulating essential cellular processes, including gene transcription and DNA replication. Some of these structures have been associated with diseases, including cancer, and mapping these regions could lead to breakthroughs in understanding health and disease.

Prior versions of ape genomes were often incomplete due to limitations in experimental methods and computational algorithms. Recent advancements in DNA sequencing and assembly technology, along with improved computational techniques, have significantly enhanced the ability to produce complete genomes. The team from Penn State has previously published similar sequencing achievements for the human Y chromosome and the sex chromosomes of living great apes.

The newly generated genome data is publicly accessible, with the research team aiming to extend this high-quality sequencing approach to gather additional data on individual apes within the studied species and explore new species, such as gibbons.