Amazing stuff!
Can you imagine a snake with legs? It's serpentine! 😊
"... In a quest to decode the secrets of snake evolution, Jia-Tang Li, a herpetologist at the Chengdu Institute of Biology, sequenced the genomes of 14 snake species. These species span 150 million years of evolution. They also looked at an additional 11 previously sequenced snake genomes. ...
To validate their findings, Li's team introduced the same mutations into the mouse equivalent of PTCH1. The results were startling—the mice exhibited significantly shorter toe bones. This evidence strongly suggests that PTCH1 could play a pivotal role in the evolution of snake leglessness. ...
The massive genome analysis also helped to shed light on other perplexing snake adaptations. Snakes have infamously poor eyesight, which is why they resort to sticking out their tongues all the time to get a sense of their surroundings. Previous studies suggested that snakes lost key genes responsible for vision. However, the new research reveals that these genes still exist within their genomes -- it's just their activity was muted and potentially silenced during early snake evolution, particularly among primitive underground-dwelling snakes."
To validate their findings, Li's team introduced the same mutations into the mouse equivalent of PTCH1. The results were startling—the mice exhibited significantly shorter toe bones. This evidence strongly suggests that PTCH1 could play a pivotal role in the evolution of snake leglessness. ...
The massive genome analysis also helped to shed light on other perplexing snake adaptations. Snakes have infamously poor eyesight, which is why they resort to sticking out their tongues all the time to get a sense of their surroundings. Previous studies suggested that snakes lost key genes responsible for vision. However, the new research reveals that these genes still exist within their genomes -- it's just their activity was muted and potentially silenced during early snake evolution, particularly among primitive underground-dwelling snakes."
From the highlights and abstract:
"Highlights
• Comprehensive chromosome-level assembly of representative snake genomes
• Reveals the genetic basis of limb loss, elongated body, and asymmetrical lungs
• Genomic variation drives blind and infrared-sensitive snake specialization
• Functional experiments validate the comparative genomic discoveries
Summary
Snakes are a remarkable squamate lineage with unique morphological adaptations, especially those related to the evolution of vertebrate skeletons, organs, and sensory systems. To clarify the genetic underpinnings of snake phenotypes, we assembled and analyzed 14 de novo genomes from 12 snake families. We also investigated the genetic basis of the morphological characteristics of snakes using functional experiments. We identified genes, regulatory elements, and structural variations that have potentially contributed to the evolution of limb loss, an elongated body plan, asymmetrical lungs, sensory systems, and digestive adaptations in snakes. We identified some of the genes and regulatory elements that might have shaped the evolution of vision, the skeletal system and diet in blind snakes, and thermoreception in infrared-sensitive snakes. Our study provides insights into the evolution and development of snakes and vertebrates.
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How did snakes lose their limbs? Mass genome effort provides clues (primary news source) DNA sequencing helps explain how these reptiles got to be so unusual
Graphical abstract
Figure 1 Phylogeny of snakes
Figure S4 Genetic bases of snake limb loss, body elongation, lung asymmetry, and eye structure simplification
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