SW New Mexico News

The cataclysmic event known as the Cretaceous-Paleogene extinction, which wiped out approximately 76% of all known species on Earth, including dinosaurs, has been a topic of intense research for years. This mass extinction, caused by an asteroid impact near what is now the Yucatan Peninsula, is believed to have paved the way for the emergence of modern birds and mammals. However, this theory has long been contested.

Peter Houde, a biology professor at New Mexico State University (NMSU), is among 52 co-authors of a recent article titled “Complexity of avian evolution revealed by family-level genomes,” set to be published in the May 23rd edition of the journal “Nature.” The paper delves into bird evolution and relationships and compares new analysis with previous research.

This research forms phase two of four in the "Birds 10,000 Genomes Project," which aims to sequence the complete genomes of all living bird species. Phase one was groundbreaking both in its magnitude and results. In contrast to phase one's sample size of 48 species representing all orders of living birds, phase two includes 363 species from 92% of all bird families. It also analyzed 50 times more DNA per species and included about 100 billion nucleotides.

Houde stated that understanding evolution's complexity and how biological processes contribute to it is only beginning. Over the past two centuries, scientists inferred relationships between birds and other organisms without genetic data. Taxonomists relied on comparative anatomy, embryology, and behavior to infer these relationships.

The study's authors found that not all genetic data are equally useful in tracking these connections. They developed strategies to target parts of the genome that mutate at a relatively constant rate over time, providing a more accurate record of how birds are related and when they evolved.

Houde's role involved using these results to calculate when various bird lineages first evolved and how their population sizes changed over the past 66 million years. The study's findings strongly support the idea that very few modern bird lineages existed before and survived the Cretaceous-Paleogene meteor impact. The authors' new approach and findings will provide opportunities to enhance future research in this area.

Houde concluded by stating that the lessons learned from this research apply to more than just birds, as birds present particularly difficult problems for evolutionary studies due to their complex history.