Abstract
Traditionally, the accumulation of new deleterious mutations in populations or species in low numbers is expected to lead to a reduction in fitness and mutational meltdown, but in this study the opposite was observed. Beginning with a highly inbred populations of Drosophila melanogaster, new mutations that accumulated in experiments of two females and two males or of one female and one male each generation for 52 generations did not cause a decline in progeny numbers over time. Only two lines went extinct among 52 tested lines. In three of four experiments there was a significant increase in progeny numbers over time (mutational firm up), which had to be due to new beneficial, compensatory, overdominant, or back mutations.
Similar content being viewed by others
References
Ashburner M (1989) Drosophila: A Laboratory Manual. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, New York, pp 192–195
Azad P, Zhang M, Woodruff RC (2010) Rapid increase in viability due to new beneficial mutations in Drosophila melanogaster. Genetica 138:251–263
Baer CJ, Miyamoto MM, Denver DR (2007) Mutation rate variation in multicellular eukaryotes: causes and consequences. Nat Rev Genet 8:619–631
Betancourt A (2007) When the going gets tough, beneficial mutations get going. Heredity 99:359–360
Charlesworth J, Eyre-Walker A (2007) The other side of the nearly neutral theory, evidence of slightly advantageous back-mutations. PNAS 104:16992–16997
Davis BH, Poon AFY, Whitlock MC (2009) Compensatory mutations are repeatable and clustered within proteins. Proc R Soc B 276:1823–1827
Dickinson WJ (2008) Synergistic fitness interactions and a high frequency of beneficial changes among mutations accumulated under relaxed selection in Saccharomyces cerevisiae. Genetics 178:1571–1578
Estes S, Lynch M (2003) Rapid fitness recovery in mutationally degraded lines of Caenorhabditis elegans. Evolution 57:1022–1030
Garbriel W, Burger R (1994) Extinction risk by mutational meltdown: synergistic effects between population regulation and genetic drift. In: Loeschke V, Tomiuk J, Kain SK (eds) Conservation genetics. Birkhauser, Basel, pp 69–84
Garcia-Dorado A, Lopez-Fanjul C, Caballero A (2004) Rates and effects of deleterious mutations and their evolutionary consequences. In: Moya A, Font E (eds) Evolution: from molecules to ecosystems. Oxford University Press, Oxford, pp 20–32
Gilligan DM, Woodworth LM, Montgomery ME, Briscoe DA, Frankham R (1997) Is mutation accumulation a threat to the survival of endangered populations? Conserv Biol 11:1235–1241
Gong Y, Woodruff RC, Thompson JN Jr (2005) Deleterious genomic mutation rate for viability in Drosophila melanogaster using concomitant sibling controls. Biol Lett 1:492–495
Haag-Liautard C, Dorris M, Maside X, Macaskill S, Halligan DL, Charlesworth B, Keightley PD (2007) Direct estimation of per nucleotide and genomic deleterious mutation rates in Drosophila. Nature 445:82–85
Halligan D, Keightley P (2009) Spontaneous mutation accumulation studies in evolutionary genetics. Annu Rev Ecol Evol Syst 40:151–172
Joseph SB, Hall DW (2004) Spontaneous mutations in diploid Saccharomyces cerevisiae: more beneficial than expected. Genetics 168:1817–1825
Lande R (1994) Risk of population extinction from new deleterious mutations. Evolution 48:1460–1469
Lande R (1995) Mutation and conservation. Conserv Biol 9:782–791
Lande R (1998) Risk of population extinction from fixation of deleterious and reverse mutations. Genetica 102(103):21–27
Lynch M, Gabriel W (1990) Mutation load and the survival of small populations. Evolution 44:1725–1737
Lynch M, Burger R, Butcher D, Gabriel W (1993) The mutational meltdown in asexual populations. Heredity 84:239–344
Lynch M, Conery J, Bürger R (1995a) Mutation accumulation and the extinction of small populations. Am Nat 146:489–518
Lynch M, Conery J, Bürger R (1995b) Mutational meltdown in sexual populations. Evolution 49:1067–1080
Lynch M, Blanchard J, Houle D, Kibota T, Schultz S, Vassilieva L, Willis J (1999) Perspective: spontaneous deleterious mutation. Evolution 53:645–663
Martin G, Lenormand T (2006) The fitness effect of mutations across environments: a survey in light of fitness landscape models. Evolution 60:2413–2427
Peck JR (1994) A ruby in the rubbish: beneficial mutations, deleterious mutations and the evolution of sex. Genetics 137:597–606
Poon A, Otto SP (2000) Compensating for our load of mutations: freezing the meltdown of small mutations. Evolution 54:1467–1479
Schultz ST, Lynch M (1997) Mutation and extinction: the role of variable mutational effects, synergistic epistasis, beneficial mutations, and degree of outcrossing. Evolution 51:1363–1371
Shaw FH, Geyer CJ, Shaw RG (2002) A comprehensive model of mutations affecting fitness and inferences for Arabidopsis thaliana. Evolution 56:453–463
Shaw RG, Shaw FH, Geyer C (2003) What fraction of mutations reduces fitness? A reply to Keightley and Lynch. Evolution 57:686–689
Whitlock MC, Burger R (2004) Fixation of new mutations in small populations. In: Ferriere R, Dieckmann U, Couvet D (eds) Evolutionary conservation biology. Cambridge University Press, Cambridge, pp 155–169
Zhang M, Azad P, Woodruff RC (2011) Adaptation of Drosophila melanogaster to increased NaCl concentration due to dominant beneficial mutations. Genetica 139:177–186
Zeyl C, Devisser J (2001) Estimates of the rate and distribution of fitness effects of spontaneous mutation in Saccharomyces cerevisiae. Genetics 157:53–61
Zeyl C, Mizesko M, de Visser JA (2001) Mutation meltdown in laboratory yeast populations. Evolution 55:909–917
Acknowledgments
The author thanks James N. Thompson, jr. for his valuable advice on this research and comments on the manuscript and Dr. Daniel Wiegmann for his advice on the statistical analyses of the data.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Woodruff, R.C. An extreme test of mutational meltdown shows mutational firm up instead. Genetica 141, 185–188 (2013). https://doi.org/10.1007/s10709-013-9716-7
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10709-013-9716-7