bat-vs-bird-evolution-wing-development

Bat vs. Bird: Uncovering the Evolutionary Differences in Wing Development

Introduction

The diversity of bats is extraordinary. Whether climbing to access blood meals, snatching insects from leaves, or hovering to feed on tropical nectar, each behavior calls for unique wing structures. This raises intriguing questions about the evolutionary path of bats and birds.

Key Questions

• Why are there no flightless bats, akin to ostriches, foraging along riverbanks for fish?
• Why haven't bats evolved to live entirely at sea, similar to the wandering albatross?

The Interconnected Evolution of Bat Wings and Legs

The latest research suggests a key distinction: unlike birds, the evolutionary paths of bat wings and legs are closely interconnected, potentiallpy limiting their ability to exploit diverse ecological niches.

Surprising Findings

"Our initial hypothesis was that bat evolution would parallel that of birds, with wings and legs developing independently. The revelation that this is not the case was highly surprising," stated Andrew Orkney, postdoctoral researcher under Brandon Hedrick at the Department of Biomedical Sciences, College of Veterinary Medicine.

Both researchers serve as co-corresponding authors for the study published on November 1 in Nature Ecology and Evolution.

Testing the Hypothesis

Researchers have long believed that, due to the distinct functions of legs and wings, the emergence of flight in vertebrates required the independent evolution of forelimbs and hindlimbs to facilitate their adaptation to different tasks. By comparing bats and birds, this hypothesis can be tested, as both groups lack a common ancestor for flight, making them valuable independent cases for examining the evolution of flight.

Methodology

• Species Analyzed: The research team analyzed the wing and leg bones of 111 bat species and 149 bird species worldwide.
• Data Sources: Their dataset comprised X-ray images of museum specimens, along with approximately one-third of newly acquired X-rays of bat specimens housed at the Cornell University Museum of Vertebrates.

Key Findings

The researchers found that in both bats and birds, the shape of the bones within a species' wing (handwing, radius, humerus) and leg (femur and tibia) are correlated, indicating that bones within a limb evolve in concert. However, when examining the correlation between legs and wings, the findings differ: bird species exhibit species exhibit minimal to no correlation, while bats demonstrate a strong correlation.

Implications of Findings

This means that, contrary to birds, the forelimbs and hindlimbs in bats evolved in tandem: changes in wing shape, whether expanding or contracting, result a similar directional change in leg shape.

Hedrick explained, "We propose that the linked evolution of wings and legs restricts bats' ability to adapt to diverse ecological environments."

Broader Implications for Evolutionary Biology

The study's results bring new questions about the evolution of pterosaurs, an extinct lineage of flying reptiles with wings resembling those of bats.

Exploring Pterosaur Diversity

"Pterosaurs were remarkably diverse, with species ranging from tiny insectivores to colossal, giraffe-sized creatures comparable to dinosaurs," Orkney explained. "What enabled them to achieve such evolutionary success?"

Further Research Directions

After this discovery, the team began a deeper investigation into the evolutionary development of bird skeletons.

Evolutionary Success of Birds

"Our findings show that birds' wings and legs evolved separately, an important factor in their evolutionary success," Orkney explained. "However, we still don't know how birds developed this trait or when it began in their lineage."

Conclusion:

For this study, a number of measurements were conducted at the Cornell Institute of Biotechnology's imaging facility.

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global-reference-genome-inequities-sequencing-resources-biodiversity

Global Reference Genome Inequities: The Critical Need for Sequencing Resources in Biodiverse Ecosystems

Introduction

Researchers from Montana State University and Universidad de los Andes have identified a notable imbalance in the distribution of tetrapod reference genomes, revealing a skewed focus on high-latitude regions rather than areas with the highest global biodiversity.

The Importance of Addressing Imbalance

The study indicates that the existing imbalance in global genomic knowledge related to ecology and evolutionary biology may significantly influence future conservation initiatives. This concern is heightened by the fact that most biological diversity resides in lower-latitude tropical regions.

The Role of Whole-Genome Sequencing (WGS)

Understanding Genetic Diversity

Whole-genome sequencing (WGS) serves as a crucial tool for:

• Exploring Genetic Diversity
• Pinpointing Adaptive Traits
• Inferring Evolutionary Relationships
• Identifying Genes with Specific Functions or Adaptations

These discernible features of a whole genome are the result of countless research projects that piece together individual gene functions across various life forms.

WGS in Conservation Genetics

Whole-genome sequencing (WGS) plays a vital role in conservation genetics by offering crucial information about the genetic health of populations. By highlighting patterns of genetic variation and inbreeding, these findings inform management practices designed to support the conservation of endangered species.

Findings from Recent Research

Publication Insights

In the publication "A Latitudinal Gradient of Reference Genomes" in the Journal Molecular Ecology, researchers reveal a significant bias in reference genomes and the identification of global tetrapod biodiversity, with a predominant concentration on species native to the Global North and midlatitudes.

Literature Review Findings

According to a Web of Science literature review on conservation genetics:

• 87% of the studies were conducted by authors from the Global North.
• WGS applications in the Global South contributing to only 1-2% of these studies.

Comparative Analysis of Datasets

Overview of Datasets

Researchers compared two datasets the Global Biodiversity Information Facility (GBIF) and the NCBI Genome Browser from the US National Institutes of Health, to analyze species sequencing priorities.

• NCBI is an open-access genomic research database that boasts the largest and most comprehensive array of sequenced genomes in the world.
• The Global Biodiversity Information Facility (GBIF) is a free online catalog that offers data on millions of species, promoting open access to information about all forms of life on Earth.

Findings from GBIF and NCBI

By refining a GBIF search to include preserved specimens from natural history museums and filtering for those with geolocation coordinates, researchers identified a total of 30,832 tetrapod specimens.

When comparing the pool of tetrapods to reference genomes accessible via the NCBI:

• Only 2,099 species (6.8%) possess assembled reference genomes.
• The majority of these sequenced species are derived from the Global North and mid-latitude regions, leaving tropical areas and the Global South significantly underrepresented. Moreover, within this limited 6.8% of species data.
• Only a small proportion originates from regions exhibiting the highest biodiversity.

The Need for Systematic Cataloging

Grounding Conservation Initiatives

Systematically cataloging Global biodiversity by location using whole-genome sequencing (WGS) is essential for grounding conservation initiatives in reliable data. An increase in sequencing data allows ecologists, evolutionary biologists, and conservation scientists to more effectively preserve the planet's diverse ecosystems and safeguard endangered species for future generations.

The Latent Function of Sequencing Data

Moreover, the authors discuss a latent function of sequencing data. Renowned scientific journals are increasingly formulating editorial guidelines that necessitate the inclusion of sequencing data, even if it is not crucial to every specific research question.

The Risk of Inaccessibility

If high-throughput sequencing resources are inaccessible to scientists working in regions where the majority of the world's species are found, we may not only be lacking certain data—we could be entirely overlooking it.

Conclusion:

The findings emphasize the urgent need for equitable access to genomic sequencing resources, particularly in biodiverse ecosystems.

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