Microsatellites: Consensus and controversy

Comparative Biochemistry and Physiology - B Biochemistry and Molecular Biology

Volumn 126, Issue 4, 2000, Pages 455-476

  Chambers, Geoffrey K ^a   MacAvoy, Elizabeth S ^a  

^a VICTORIA UNIVERSITY OF WELLINGTON   (New Zealand)

Author keywords

Allele frequency spectra; DNA repair; DNA synthesis; Infinite alleles model; Microsatellites; Neutral theory; Simple tandem repeats; Stepwise mutation model; Tuatara (Sphenodon punctatus)

Indexed keywords

DNA;

ALLELE; DNA REPAIR; DNA SEQUENCE; GENE FREQUENCY; GENE MUTATION; NONHUMAN; NUCLEOTIDE SEQUENCE; PRIORITY JOURNAL; REVIEW;

SERPENTES; SPHENODON PUNCTATUS;

EID: 0033867122     PISSN: 03050491     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0305-0491(00)00233-9     Document Type: Review

References (120)

1. Amos, W.A. (1999) A comparative approach to the study on microsatellite evolution. In: Goldstein, D.B., Schlötterer, C. (Eds.), Microsatellites: Evolution and Applications. Oxford University Press, Oxford, pp. 66-79.
2. Amos, W., Sawcer, S.J., Feakes, R.W., Rubinsztein, D.C., 1996. Microsatellites show mutational bias and heterozygote instability. Nat. Genet. 13, 390-391.
3. Anon, 1996. Romanovs find closure in DNA. Nat. Genet. 12, 339-340.
4. Armour, J.A.L., Neuman, R., Gobert, S., Jeffreys, A.J., 1994. Isolation of human simple repeat loci by hybridisation selection. Hum. Mol. Genet. 3, 599-605.
5. Armour, J.A.L., Alegre, S.A., Miles, S., Williams, L.J., Badge, R.M., 1999. Minisatellites and mutation processes in tandemly repetitive DNA. In: Goldstein, D.B., Schlötterer, C. (Eds.), Microsatellites: Evolution and Applications. Oxford University Press, Oxford, pp. 24-33.
6. Ashton, R.M., 1999. Genetic Diversity and Population Structure of the New Zealand Sea Lion (Phocarctos hookeri). MSc Thesis, Auckland University.
7. Beckmann, J.S., Weber, J.L., 1992. Survey of human and rat microsatellites. Genomics 12, 627-631.
8. Brinkmann, B., Klintschar, M., Neuhuber, F., Hühne, J., Rolf, B., 1998. Mutation rate in human microsatellites: influence of the structure and length of the tandem repeat. Am. J. Hum. Genet. 62, 1408-1415.
9. Britten, R.J., Kohne, D.E., 1968. Repeated sequences in DNA. Science 161, 529-540.
10. Brohede, J, Ellegren, H., 1999. Microsatellite evolution: Polarity of substitutions within repeats and neutrality of flanking substitutions. Proc. R. Soc. Lond. B 266, 825-833.
11. Brooker, A.L., Cook, C., Bentzen, P., Wright, J.M., Doyle, R.W., 1994. Organisation of microsatellites differs between mammals and cold-water teleost fishes. Can. J. Fish Aquat. Sci. 51, 1959-1966.
12. Bruford, M.W., Cheesman, D.J., Coote, T., Green, H.A.A., Haines, S.A., O'Ryan, C., William, T.R., 1996. Microsatellites and their application to conservation genetics. In: Smith, T.B., Wayne, R.K. (Eds.), Molecular Genetic Approaches in Conservation. Oxford University Press, New York, pp. 278-297.
13. Buchanan, F.C., Maiers, L.D., Thue, T.D., De March, B.G.E., Stewart, R.E.A., 1998. Microsatellites from the Atlantic walrus, Odobenus rosmarus. Mol. Ecol. 7, 1083-1090.
14. n microsatellite markers. Am. J. Hum. Genet. 52, 922-927.
15. Cavalli-Sforza, L.L., Edwards, A.W.F., 1967. Phylogenetic analysis: models and estimation procedures. Am. J. Hum. Genet. 19, 233-257.
16. Chambers, G.K., Cordiner, S.J., Buckleton, J., Vignaux, A., Robertson, B., 1997. Forensic DNA profiling: the importance of giving correct answers to the right questions. Criminal Law Forum 8, 445-459.
17. Cooper, G., 1995. Analysis of Genetic Variation and Sperm Competition in Dragonflies. D. Phil. Thesis, Oxford University.
18. Cooper, G., Rubinsztein, D.C., Amos, W., 1998. Ascertainment bias cannot entirely account for human microsatellites being longer than their chimpanzee homologues. Hum. Mol. Genet. 7, 1425-1429.
19. Crawford, A.M., Kappes, S.M., Paterson, K., de Gotari, M.J., Dodds, K.G., Freking, B., Stone, R.T., Beattie, C.W., 1998. Microsatellite evolution: testing the ascertainment bias hypothesis. J. Mol. Evol. 46, 256-260.
20. Crow, J.F., Kimura, M., 1970. An Introduction to Population Genetics Theory. Harper and Row, New York.
21. Curach, N., Sunnucks, P., 1999. Molecular anatomy' of an onychophoran: compartmentalized sperm storage and heterogeneous paternity. Mol. Ecol. 8, 1375-1385.
22. de Gortari, M.J., Freking, B.A., Cuthbertson, R.P., Kappes, S.M., Keele, J.W., Stone, R.T., Leymaster, K.A., Dodds, K.G., Crawford, A.M., Beattie, C.W., 1999. A second-generation linkage map of the sheep genome. Mamm. Genome 9, 204-209.
23. Dib, C., Fauré, S., Fizames, C., Samson, D., Drouot, N., Vignal, A., et al., 1996. A comprehensive map of the human genome based on 5264 microsatellites. Nature 380, 152-154.
24. Dietrich, W.F., Miller, J., Steen, R., Merchant, M.A., Damron-Boles, D., Husain, Z., et al., 1996. A comprehensive genetic map of the mouse genome. Nature 380, 149-152.
25. Di Rienzo, A., Peterson, A.C., Garza, J.C., Valdes, A.M., Slatkin, M., Freimer, N.B., 1994. Mutational processes of simple-sequence repeat loci in human populations. Proc. Natl. Acad. Sci. USA 91, 3166-3170.
26. Edwards, A., Hammond, H.A., Jin, L., Caskey, C.T., Chakraborty, R., 1992. Genetic variation of five trimeric and tetrameric tandem repeat loci in four human population groups. Genomics 12, 241-253.
27. Eisen, J.A., 1999. Mechanistic basis for microsatellilte instability. In: Goldstein, D.B., Schlötterer, C. (Eds.), Microsatellites: Evolution and Applications. Oxford University Press, Oxford, pp. 34-48.
28. Ellegren, H., Primmer, C.R., Sheldon, B.C., 1995. Microsatellite evolution: directionality or bias in locus selection. Nat. Genet. 11, 360-362.
29. Ellegren, H., Moore, S., Robinson, N., Byrne, K., Ward, W., Sheldon, B.C., 1997. Microsatellite evolution - a reciprocal study of repeat lengths at homologous loci in cattle and sheep. Mol. Biol. Evol. 14, 854-860.
30. Estoup, A., Garnery, L., Solignac, M., Cornuet, J-M., 1995a. Microsatellite variation in honey bee (Apis melifera L.) populations: hierarchical genetic structure and test of the infinite allele and stepwise mutation model. Genetics 140, 679-695.
31. Estoup, A., Tailliez, C., Cornuet, J-M., Solignac, M., 1995b. Size homoplasy and mutational processes of interrupted microsatellites in two bee species, Apis mellifera and Bombus terrestris (Apidae). Mol. Biol. Evol. 12, 1074-1084.
32. Estoup, A., Cornuet, J-M., 1999. Microsatellite evolution: inferences from population data. In: Goldstein, D.B., Schlötterer, C. (Eds.), Microsatellites: Evolution and Applications. Oxford University Press, Oxford, pp. 49-65.
33. Falush, D., Iwasa, Y, 1999. Size-dependent mutability and microsatellite constraints. Mol. Biol. Evol. 16, 960-966.
34. Feldman, M.W., Bergman, A., Pollock, D.D., Goldstein, D.B., 1997. Microsatellite genetic distances with range constraints: analytic description and problems of estimation. Genetics 145, 207-216.
35. FitzSimmons, N.N., Moritz, C., Moore, S.S., 1995. Conservation and dynamics of microsatellite loci over 300 years of marine turtle evolution. Mol. Biol. Evol. 12, 4322-4440.
36. Freudenreich, C.H., Stavenhagen, J.B., Zakian, V.A., 1997. Stability of a CTG/CAG trinucleotide repeat in yeast is dependent on its orientation in the genome. Mol. Cell Biol. 4, 2090-2098.
37. Garza, J.C., Slatkin, M., Freimer, N.B., 1995. Microsatellite allele frequencies in humans and chimpanzees, with implications for constraints on allele size. Mol. Biol. Evol. 12, 594-603.
38. Gemmell, N.J., Allen, P.J., Goodman, S.J., Reed, J.Z., 1997. Interspecific microsatellite markers for the study of pinniped populations. Mol. Ecol. 6, 661-666.
39. Gill, P., Ivanov, P.L., Kimpton, C., Piercy, R., Benson, N., Evett, I., Hagelberg, E., Sullivan, K., 1994. Identification of the remains of the Romanov family by DNA analysis. Nat. Genet. 6, 130-135.
40. Goldstein, D.B., Clark, A.G., 1995. Microsatellite variation in North American populations of Drosophila melanogaster. Nucl. Acids Res. 23, 3882-3886.
41. Goldstein, D.B., Linares, A.R., Cavalli-Sforza, L.L., Feldman, M.W., 1995a. An evaluation of genetic distances for use with microsatellite data. Genetics 139, 463-471.
42. Goldstein, D.B., Linares, A.R., Cavalli-Sforza, L.L., Feldman, M.W., 1995b. Genetic absolute dating based on microsatellites and the origin of modern humans. Proc. Natl. Acad. Sci. USA 92, 6723-6727.
43. Goldstein, D.B., Pollock, D.D., 1997. Launching microsatellites: a review of mutation processes and methods of phylogenetic inference. J. Hered. 88, 335-342.
44. Goldstein, D.B., Schlötterer, C. (Eds.), 1999. Microsatellites: Evolution and Applications. Oxford University Press, Oxford.
45. Goodman, S.J., 1995. Molecular Population Genetics of the European Harbour Seal (Phoca vitulina) with Reference to the 1988 Phocine Distemper Virus Epizootic. PhD thesis, Cambridge University.
46. Goodman, S.J., 1997. RST Cale: a collection of computer programmes for calculating estimates of genetic differentiation from microsatellite data and determining their significance. Mol. Ecol. 6, 881-885.
47. Gordenin, D.A., Kunkel, T.A., Resnick, M.A., 1997. Repeat expansion-all in a flap? Nat. Genet. 16, 116-118.
48. Gordon, A.J.E., 1997. Microsatellite birth register. J. Mol. Evol. 45, 337-338.
49. Haberl, M., Tautz, D., 1999. Comparative allele sizing can produce inaccurate allele size differences for microsatellites. Mol. Ecol. 8, 1347-1350.
50. Hammond, R.L., Saccheri, I.J., Ciofi, C., Coote, T., Funk, S.M., McMillan, W.O., Bayes, M.K., Taylor, E., Bruford, M.W., 1998. Isolation of microsatellite markers in animals. In: Karp, A., Issac, P.G., Ingram, D.S. (Eds.), Molecular Tools for Screening Biodiversity. Chapman and Hall, London, pp. 279-287.
51. Hancock, J.M., 1999. Microsatellites and other simple sequences: genomic context and mutational mechanisms. In: Goldstein, D.B., Schlötterer, C. (Eds.), Microsatellites: Evolution and Applications. Oxford University Press, Oxford, pp. 1-9.
52. Hearne, C.M., Gosh, S., Todd, J.A., 1992. Microsatellites for linkage analysis of genetic traits. Trends Genet. 8, 288-294.
53. Hedrick, P.W., 1999. Perspective: Highly variable loci and their interpretation in evolution and conservation. Evolution 53, 313-318.
54. Henderson, S.T., Petes, T.D., 1992. Instability of simple sequence DNA in Saccaromyces cerevisiae. Mol. Cell Biol. 12, 2749-2757.
55. Jarne, P., Lagoda, P.J.L., 1996. Microsatellites, from molecules to populations and back. Trends Ecol. Evol. 11, 424-429.
56. Jeffreys, A.J., Wilson, V., Thein, S.W., 1985. Hypervariable minisatellite regions in human DNA. Nature 314, 67-73.
57. Jin, L., Macaubas, C., Hallmayer, J., Kimura, A., Mignot, E., 1996. Mutation rate varies among alleles at a microsatellite locus: phylogenetic evidence. Proc. Natl. Acad. Sci. USA 93, 15285-15288.
58. Karp, A., Isaac, P.G., Ingram, D.S. (Eds.), 1998. Molecular Tools for Screening Biodiversity: Plants and Animals. Chapman and Hall, London.
59. Kimmel, M., Chakraborty, R., Stivers, D.N., Deka, R., 1996. Dynamics of repeat polymorphisms under a forward-backward model: within- and between-population variability at microsatellite loci. Genetics 143, 549-555.
60. Kimpton, C.P., Gill, P., Walton, A., Urquhart, A., Millican, E.S., Adams, M., 1993. Automated DNA profiling employing multiplex amplification of short tandem repeat loci, PCR. Methods Appl. 3, 13-22.
61. Kimura, M., Crow, J.F., 1964. The number of alleles that can be maintained in a finite population. Genetics 49, 725-738.
62. Kimura, M., 1993. The Neutral Theory of Molecular Evolution. Cambridge University Press, Cambridge.
63. Kolodner, R., 1996. Biochemistry and genetics of eukaryotic mismatch repair. Genes Dev. 10, 1433-1442.
64. Kruglyak, S., Durrett, R.T., Schug, M.D., Aquadro, C.F., 1998. Equilibrium distributions of microsatellite repeat length resulting from a balance between slippage events and point mutations. Proc. Natl. Acad. Sci. USA 95, 10774-10778.
65. Lehman, T., Hawley, W.A., Grebert, H., Collins, F.H., 1998. The effective population size of Anopheles gambiae in Kenya: implications for population structure. Mol. Biol. Evol. 15, 264-276.
66. Levinson, G., Gutman, G.A., 1987. Slipped-strand mispairing: a major mechanism for DNA sequence evolution. Mol. Biol. Evol. 4, 203-221.
67. Litt, M., Luty, J.M., 1989. A hypervariable microsatellite revealed by in vitro amplification of a dinucleotide repeat within the cardiac muscle actin gene. Am. J. Hum. Genet. 44, 397-401.
68. Luikhart, G., England, P.R., 1999. Statistical analysis of microsatellite DNA data. Trends Ecol. Evol. 14, 253-256.
69. Lynch, M., Milligan, B.G., 1994. Analysis of population genetic structure with RAPD markers. Mol. Biol. Evol. 7, 91-99.
70. McDonald, D.B., Potts, W.K., 1997. DNA microsatellites as genetic markers for several scales. In: Mindell, D.P. (Ed.), Avian Molecular Evolution and Systematics. Academic Press, San Diego, pp. 29-49.
71. Messier, W., Li, S-H., Stewart, C-B., 1996. The birth of microsatellites. Nature 381, 483.
72. Meyer, E., Wiegand, P., Rand, S.P., Kuhlman, E., Brack, M., Brinkmann, B., 1995. Microsatellite polymorphisms reveal phylogenetic relationships in primates. J. Mol. Evol. 41, 10-14.
73. Nakamura, Y., Leppert, M., O'Connel, P., Wolff, R., Holm, T., Culver, M., Martin, C., Fujimoto, E., Hoff, M., Kumlin, E., White, R., 1987. Variable number tandem repeat (VNTR) markers for human gene mapping. Science 235, 1616-1622.
74. National Research Council, 1992. DNA Technology in Forensic Science. National Academy Press, Washington DC.
75. National Research Council, (1996) The Evaluation of Forensic DNA Evidence. Washington DC, National Academy Press.
76. Nauta, M.J., Weissing, F.J., 1996. Constraints on allele size at microsatellite loci: implications for genetic differentiation. Genetics 143, 1021-1032.
77. Nei, M., 1987. Molecular Evolutionary Genetics. Columbia University Press, New York.
78. Nielsen, E.E., Hansen, M.M., Loeschcke, V., 1999. Genetic variation in time and space: microsatellite analysis of extinct and extant populations of Atlantic salmon. Evolution 53, 261-268.
79. Ohta, T., Kimura, M., 1973. The model of mutation appropriate to calculate the number of electrophoretically detectable alleles in a genetic population. Genet. Res. 22, 201-204.
80. Petes, T.D., Greenwell, P.W., Dominska, M., 1997. Stabilization of microsatellite sequences by variant repeats in the yeast Saccaromyces cerevisiae. Genetics 146, 491-498.
81. Pérez, T., Albornoz, J., Dominguez, A., 1998. An evaluation of RAPD fragment reproducibility and nature. Mol. Ecol. 7, 1347-1357.
82. Primmer, C.R., Ellegren, H., Saino, N., Møller, A.P., 1996. Directional evolution in germline microsatellite mutations. Nat. Genet. 13, 391-393.
83. Primmer, C.R., Ellegren, H., 1998. Pattern of molecular evolution in avian microsatellites. Mol. Biol. Evol. 15, 997-1008.
84. Richards, R.I., Sutherland, G.R., 1994. Simple repeat DNA is not replicated simply. Nat. Genet. 6, 114-116.
85. Rose, O., Falush, D., 1998. A threshold size for microsatellite expansion. Mol. Biol. Evol. 15, 613-615.
86. Rubinsztein, D.C., Leggo, J., Amos, W., 1995. Microsatellites evolve more rapidly in humans than in chimpanzees. Genomics 30, 610-615.
87. Rubinsztein, D.C., 1999. Trinucleotide expansion mutations cause diseases which do not conform to classical Mendelian expectations. In: Goldstein, D.B., Schlötterer, C. (Eds.), Microsatellites: Evolution and Applications. Oxford University Press, Oxford, pp. 80-97.
88. Schlötterer, C., Tautz, D., 1992. Slippage synthesis of simple sequence DNA. Nucl. Acids Res. 20, 211-215.
89. Schlötterer, C., 1998. Microsatellites. In: Hoelzel, A.R. (Ed.), Molecular Genetic Analysis of Populations: A Practical Approach. IRL Press, Oxford, pp. 237-261.
90. Shibata, D., 1999. Microsatellite analysis of human tumours. In: Goldstein, D.B., Schlötterer, C. (Eds.), Microsatellites: Evolution and Applications. Oxford University Press, Oxford, pp. 266-274.
91. Shriver, M.D., Jin, L., Chakraborty, R., Boerwinkle, E., 1993. VNTR allele frequency distributions under the stepwise mutation model: a computer simulation approach. Genetics 134, 983-993.
92. Sia, E.A., Jinks-Roberston, S., Petes, T.D., 1997a. Genetic control of microsatellite stability. Mutat. Res. 383, 61-70.
93. Sia, E.A., Kokoska, R.J., Dominska, M., Greenwell, P., Petes, T.D., 1997b. Microsatellite instability in yeast: dependence on repeat unit size and DNA mismatch repair genes. Mol. Cell Biol. 17, 2851-2858.
94. Slatkin, M., 1995. A measure of population subdivision based on microsatellite allele frequencies. Genetics 139, 457-462.
95. Strand, M., Prolla, T.A., Kiskay, R.M., Petes, T.D., 1993. Destabilization of tracts of simple repetitive DNA in yeast by mutations affecting DNA mismatch repair. Nature 365, 274-276.
96. Strand, M., Earley, M., Crouse, C.F., Petes, T.D., 1995. Mutations in the MSH3 gene preferentially lead to deletions within tracts of simple repetitive DNA in Saccaromyces cerevisiae. Proc. Natl. Acad. Sci. USA 92, 10418-10421.
97. Sunnucks, P., England, P.R., Taylor, A.C., Hales, D.F., 1996. Microsatellite and chromosome evolution of parthenogenetic Sitobion aphids in Australia. Genetics 144, 747-756.
98. Sunnucks, P., De Bario, P.J., Lushai, G., Maclean, N., Hales, D., 1997. Genetic structure of an aphid studied using microsatellites: cyclic parthenogenesis, differentiated lineages and host specialization. Mol. Ecol. 6, 1059-1073.
99. Taberlet, P., Waits, L.P., Luikart, G., 1999. Non-invasive sampling; look before you leap. Trends Ecol. Evol. 14, 323-327.
100. Takezaki, N., Nei, M., 1996. Genetic distances and reconstruction of phylogenetic trees from microsatellite DNA. Genetics 114, 389-399.
101. Tautz, D., 1989. Hypervariability of simple sequences as a general source for polymorphic DNA markers. Nucl. Acids Res. 17, 6463-6471.
102. Tautz, D., Trick, M., Dover, G.A., 1986. Cryptic simplicity in DNA is a major source of genetic variation. Nature 322, 652-656.
103. Tautz, D., 1993. Notes on definition and nomenclature of tandemly repetitive DNA sequences. In: Pena, D.J., Chakraborty, R., Epplen, J.T., Jeffreys, A.J. (Eds.), DNA Fingerprinting: State of the Science. Birkhäuser Verlag, Basel, pp. 21-28.
104. Taylor, A.C., Horsup, A., Johnson, C.N., Sunnucks, P., Sherwin, B., 1997. Relatedness structure detected by microsatellite analysis and attempted pedigree reconstruction in an endangered marsupial, the northern hairy-nosed wombat Lasiorhinus kreffti. Mol. Ecol. 6, 9-19.
105. Tessier, N., Bernatchez, L., 1999. Stability of population structure and genetic diversity across generations assessed by microsatellites among sympatric populations of landlocked Atlantic salmon (Salmo salar L.). Mol. Ecol. 8, 169-179.
106. Ueno, S., Yoshimaru, H., Tomaru, N., Yamamoto, S., 1999. Development and characterization of microsatellite markers in Camelia japonica L. Mol. Ecol. 8, 335-336.
107. Ujino, T., Kawahara, T., Tsumura, Y., Nagamitsu, T., Yoshimaru, H., Wickneswari, R., 1998. Development and polymorphism of simple sequence repeat DNA markers for Shorea curtisii and other Dipterocarpaceae species. Heredity 81, 422-428.
108. Valdes, A.M., Slatkin, M., Freimer, N.B., 1993. Allele frequencies at microsatellite loci: the stepwise mutation model revisited. Genetics 133, 737-749.
109. Valsecchi, E., Palsbøll, P., Hale, P., Glockner-Ferrari, D., Ferrari, M., Clapham, P., Larsen, F., Mattilla, D., Sears, R., Sigurjonsson, J., Brown, M., Corkerton, P., Amos, B., 1997. Microsatellite genetic distances between oceanic populations of the humpback whale (Megaptera novaeangliae). Mol. Biol. Evol. 14, 355-362.
110. n polymorphisms. Genomics 7, 524-530.
111. Weber, J.L., May, P.E., 1989. Abundant class of human DNA polymorphisms which can be typed using the polymerase chain reaction. Am. J. Hum. Genet. 44, 388-396.
112. Weber, J.L., Wong, C., 1993. Mutation of human short tandem repeats. Hum. Mol. Genet. 2, 1123-1128.
113. Weir, B.S., Cockerham, C.C., 1984. Estimating F-statistics for the analysis of population structure. Evolution 38, 1358-1370.
114. Wierdl, M., Greene, C.M., Datta, A., Jinks-Roberston, S., Petes, T.D., 1996. Destabilisation of simple repeat sequences by transcription in yeast. Genetics 146, 713-721.
115. Wierdl, M., Dominska, M., Petes, T.D., 1997. Microsatellite instability in yeast: dependence on the length of the microsatellite. Genetics 146, 769-779.
116. Wilson, A.C.C., Sunnucks, P., Hales, D.F., 1997. Random loss of X chromosome at male determination in an aphid Sitobion near fragariae, detected using an X-linked polymorphic microsatellite marker. Genet. Res. Camb. 69, 233-236.
117. Wright, S., 1951. The genetical structure of populations. Ann. Eugenics 15, 323-354.
118. Zheng, L., Collins, F.H., Kumar, V., Kafatos, F.C., 1993. A detailed genetic map of the X chromosome of the malaria vector, Anopheles gambiae. Science 261, 605-608.
119. Zhivotovsky, L.A., Feldman, M.W., 1995. Microsatellite variability and genetic distance. Proc. Natl. Acad. Sci. USA 92, 11549-11552.
120. Zhivotovsky, L.A., Feldman, M.W., Grishechkin, S.A., 1997. Biased mutation and microsatellite variation. Mol. Biol. Evol. 14, 926-933.