Mammalian Genome

, Volume 8, Issue 2, pp 134–138

Analysis of mutation rates in the SMCY/SMCX genes shows that mammalian evolution is male driven

  • A. I. Agulnik
  • C. E. Bishop
  • J. L. Lerner
  • S. I. Agulnik
  • V. V. Solovyev
Original Contribution

DOI: 10.1007/s003359900372

Cite this article as:
Agulnik, A.I., Bishop, C.E., Lerner, J.L. et al. Mammalian Genome (1997) 8: 134. doi:10.1007/s003359900372

Abstract

Mammalian evolution is believed to be male driven because the greater number of germ cell divisions per generation in males increases the opportunity for errors in DNA replication. Since the Y Chromosome (Chr) replicates exclusively in males, its genes should also evolve faster than X or autosomal genes. In addition, estimating the overall male-to-female mutation ratio (αm) is of great importance as a large αm implies that replication-independent mutagenic events play a relatively small role in evolution. A small αm suggests that the impact of these factors may, in fact, be significant. In order to address this problem, we have analyzed the rates of evolution in the homologous X-Y common SMCX/SMCY genes from three different species—mouse, human, and horse. The SMC genes were chosen because the X and Y copies are highly homologous, well conserved in evolution, and in all probability functionally interchangeable. Sequence comparisons and analysis of synonymous substitutions in approximately 1kb of the 5′ coding region of the SMC genes reveal that the Y-linked copies are evolving approximately 1.8 times faster than their X homologs. The male-to-female mutation ratio αm was estimated to be 3. These data support the hypothesis that mammalian evolution is male driven. However, the ratio value is far smaller than suggested in earlier works, implying significance of replication-independent mutagenic events in evolution.

Copyright information

© Springer-Verlag 1997

Authors and Affiliations

  • A. I. Agulnik
    • 1
  • C. E. Bishop
    • 1
    • 2
  • J. L. Lerner
    • 3
  • S. I. Agulnik
    • 4
  • V. V. Solovyev
    • 5
  1. 1.Department of Obstetrics and GynecologyBaylor College of MedicineHoustonUSA
  2. 2.Department of Human and Molecular GeneticsBaylor College of MedicineHoustonUSA
  3. 3.Department of Obstetrics and GynecologyUniversity of TennesseeMemphisUSA
  4. 4.Department of Molecular BiologyPrinceton UniversityPrincetonUSA
  5. 5.Department of Cell BiologyBaylor College of MedicineHoustonUSA