El origen de la vida

1. El origen de la vida Título: "El origen de la vida" Reseña: ¿De dónde provienen los seres vivos? La teoría quimiosintética, formulada por Alexander Oparin en 1938, sugiere que los primeros seres vivos se originaron a partir de compuestos orgánicos que se formaron abióticamente en la Tierra primitiva. Posteriormente, en 1953, Stanley Miller inició la investigación experimental en origen de la vida, al obtener aminoácidos simulando las condiciones existentes en la Tierra, previas al origen de la vida. En está plática revisaremos algunos de los avances científicos que nos permiten entender un poco mejor esta pregunta fundamental de las ciencias biológicas.

3. ¿Cómo se originó la vida?

4. origin of life ? living systems non-living matter

5. Therefore I should infer from analogy that probably all the organic beings which have ever lived on this earth have descended from some one primordial form, into which life was first breathed. The Origin of Species Darwin (1859)

7. Alexander Oparin (1894-1980) J.B.S. Haldane (1892-1964)

8. Heterotrophic origin of life reducing atmosphere synthesis of organic compounds & formation of the primitive soup coacervates primordial heterotrophs

9. Early abiotic synthesis of biochemical compounds 1) Proust 1807 HCN polymer + adenine (?) 2) Wöhler 1828 NH4NCO urea 3) Strecker 1850 CH3CHO + NH3 + HCN alanine 4) Butlerow 1861 HCHO sugars OH- OH-

10. Stanley Miller (1930-2007) 1953

11. Harold C. Urey’s primitive terrestrial atmosphere C + 2H2 -> CH4 N2 + 3H2 -> NH3 O2 + 2H2 -> H2O S + H2 -> H2S CO2 + 6H2 -> CH4 + 2H2O

12. The 1953 Miller experiment

14. Abiotic synthesis of amino acids Miller, 1953

15. 1953: Annus mirabilis Watson & Crick Double-helix model of DNA Sanger & Thompson Complete sequencing of a protein Prebiotic synthesis of organic compounds S. L. Miller

17. 5 HCN adenine Joan Oró

18. 5 HCN adenine Joan Oró

20. Prebiotic syntheses that work 1. Amino acids from Strecker synthesis 2. Purines from HCN polymerization 3. Pyrimidines from cyanoacetylene & urea 4. Sugars from HCHO polymerization

21. ?

22. Abiotic synthesis under hydrothermal vent conditions FeS + H2S -> FeS2 + H2 NiS/FeS 2CH3-SH + CO CH3CO(SCH3) + H2S CH3-SH + CO + H2O CH3-COOH + H2S amino acids + CO dipeptides NiS/FeS NiS/FeS

23. Some interstellar molecules H2, OH, SiS, HCl, NaCl, KCl, CH, CH+,CN, CO, CS, C2 H2O, H2S, N2H+, SO2, HCO+, HCN, C2H, C3, C2O, COS NH3, H2CO, HNCO, H2CS,C2H2 SiH4, HC3N, H2CN, CH4,C5, H2C=C=O, HCOOH, HNCO CH3OH, CH3CCN, HCONH2 CH3COH, CH3C2H, CH3NH2, H2CCHCN, HC5N HCOOCH3, CH3CH2, (CH3) 2O, HCN7N HC9N, HC11N

24. Extrasolar planetary systems

25. An extraterrestrial origin of organic compounds? The Murchison meteorite Meteor Crater, Arizona

26. Compounds in the Murchison meteorite aromatic hydrocarbons alcohols (C1-C4) aliphatic hydrocarbons aldehydes (C2-C4) sulfonic acids polyols (C2-C4) phosphonic acids monocarboxylic acids (C1-C8) ketones (C3-C5) dicarboxylic acids (C2-C5) hydroxy acids (C2-C9) amines (C1-C4) amino acids pyridines urea quinolines purines polypyrroles pyrimidines

28. Closing in on a time frame for the origin of life on Earth ? cooling of the Earth impact frustrations fossil record 4.5 4.0 3.5 3.0 The age of the Earth (billions of years ago)

29. Prebiotic sources of organic compounds 1) anoxic interfase ocean/atmosphere 2) input in meteorites 3)high-temperature vent chemistry

30. reducing environments NH3 CH4 HCN extraterrestrial organics pyrite primordial soup

31. Fraser et al (1997)

32. origin of life ? living systems prebiotic soup

34. M + B + T Metabolism + Boundaries + Template based reproduction of hereditary material Szathmary et al. 2005

35. reproduction (replication) metabolism (catalysis) replication protometabolism protometabolism replication protometabolism prebiotic organic compounds METABOLIC VIEW GENETIC VIEW

36. *A *U *A *A *U A U U *U A *U *A montmorillonite Ferris 2002

38. Szostak, Bartel, & Luisi (2001) Nature409: 387

40. The study of the origin and early evolution of life ? (Modified from Lazcano & Miller, 1999)‏