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cover of episode All of life has a common ancestor. What was LUCA?

All of life has a common ancestor. What was LUCA?

2025/1/17
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Jonathan Lambert: 我研究了LUCA，也就是所有生命的最后共同祖先。它是一种已经灭绝的单细胞生物，存在于数十亿年前。通过追溯生命树上任何两个物种的进化路径，最终都会汇聚到LUCA这个共同的祖先。我们研究LUCA，是为了了解所有地球生命的起源。最近一项研究表明，LUCA可能比我们之前认为的更古老、更复杂。 我们通过研究所有生物体共享的基因和蛋白质来推断LUCA的特征。然而，水平基因转移和基因丢失等因素会干扰我们的研究。2016年的一项研究认为LUCA比较简单，依赖于热液喷口生存。但新的研究表明，LUCA可能拥有更复杂的基因组，大约有2600个蛋白质，并且拥有CRISPR-Cas9基因，这表明它可能拥有古老的免疫系统。 LUCA可能生活在无氧环境中，利用二氧化碳或氢气获取能量。它可能生活在热液喷口附近，也可能生活在靠近海洋表面的地方。一些研究人员认为，LUCA并非单独存在，而是生活在一个复杂的微生物生态系统中。 研究人员利用基因突变作为分子钟，并结合碳定年化石，估算LUCA生存年代约为42亿年前。这个结果引发了一些争议，但如果准确，则表明复杂生命在地球上进化可能并不困难，这对于地外生命的存在具有重要意义。 Emily Kwong: 作为节目的主持人，我与Jonathan Lambert讨论了关于LUCA的最新研究成果。我们探讨了如何通过研究现存生物的共同特征来推断LUCA的特征，以及水平基因转移和基因丢失等因素如何影响研究结果。我们还讨论了关于LUCA生存年代和生活环境的最新研究发现，以及这些发现对我们理解生命起源和地外生命存在的意义。

Deep Dive

Chapters
This chapter introduces LUCA, the last universal common ancestor of all life on Earth. It discusses the concept of the tree of life and how all species trace back to this single-celled organism. The chapter also introduces Jonathan Lambert, an expert on LUCA, and previews the show's exploration of LUCA's characteristics and implications.
  • LUCA is the last universal common ancestor of all life.
  • All life on Earth shares fundamental machinery of life, suggesting a common ancestor.
  • A new study suggests LUCA may be older and more complex than previously thought.

Shownotes Transcript

Imagine the tree of life. The tip of every branch represents one species, and if you follow any two branches back through time, you'll hit an intersection. If you keep going back in time, you'll eventually find the common ancestor for all of life. That ancestor is called LUCA, the last universal common ancestor, and there is no fossil record to tell us what it looked like. Luckily, we have Jonathan Lambert. He's a science correspondent for NPR and today he's talking all things LUCA: What we think this single-celled organism may have looked like, when it lived and why a recent study suggests it could be older and more complex than scientists thought. *Have other questions about ancient biology? Email us at [email protected]) — we'd love to hear from you!Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave).*Learn more about sponsor message choices: podcastchoices.com/adchoices)NPR Privacy Policy)