Gene conversion drives the evolution of HINTW, an ampliconic gene on the female-specific avian W chromosome

被引:55
作者
Backström, N [1 ]
Ceplitis, H [1 ]
Berlin, S [1 ]
Ellegren, H [1 ]
机构
[1] Uppsala Univ, Evolutionary Biol Ctr, Dept Evolutionary Biol, Uppsala, Sweden
关键词
gene conversion; concerted evolution; multicopy gene; sex chromosomes; GC content; mutation rate; chicken;
D O I
10.1093/molbev/msi198
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
The HINTW gene on the female- specific W chromosome of chicken and other birds is amplified and present in numerous copies. Moreover, as HINTW is distinctly different from its homolog on the Z chromosome ( HINTZ), is a candidate gene in avian sex determination, and evolves rapidly under positive selection, it shows several common features to ampliconic and testis- specific genes on the mammalian Y chromosome. A phylogenetic analysis within galliform birds ( chicken, turkey, quail, and pheasant) shows that individual HINTW copies within each species are more similar to each other than to gene copies of related species. Such convergent evolution is most easily explained by recurrent events of gene conversion, the rate of which we estimated at 10(-6) -10(-5) per site and generation. A significantly higher GC content of HINTW than of other W- linked genes is consistent with biased gene conversion increasing the fixation probability of mutations involving G and C nucleotides. Furthermore, and as a likely consequence, the neutral substitution rate is almost twice as high in HINTW as in other W- linked genes. The region on W encompassing the HINTW gene cluster is not covered in the initial assembly of the chicken genome, but analysis of raw sequence reads indicates that gene copy number is significantly higher than a previous estimate of 40. While sexual selection is one of several factors that potentially affect the evolution of ampliconic, male- specific genes on the mammalian Y chromosome, data from HINTW provide evidence that gene amplification followed by gene conversion can evolve in female- specific chromosomes in the absence of sexual selection. The presence of multiple and highly similar copies of HINTW may be related to protein function, but, more generally, amplification and conversion offers a means to the avoidance of accumulation of deleterious mutations in nonrecombining chromosomes.
引用
收藏
页码:1992 / 1999
页数:8
相关论文
共 53 条
[1]   Why are female birds ornamented? [J].
Amundsen, T .
TRENDS IN ECOLOGY & EVOLUTION, 2000, 15 (04) :149-155
[2]   Distinct changes of genomic biases in nucleotide substitution at the time of mammalian radiation [J].
Arndt, PF ;
Petrov, DA ;
Hwa, T .
MOLECULAR BIOLOGY AND EVOLUTION, 2003, 20 (11) :1887-1896
[3]   Comparison of the chicken and turkey genomes reveals a higher rate of nucleotide divergence on microchromosomes than macrochromosomes [J].
Axelsson, E ;
Webster, MT ;
Smith, NGC ;
Burt, DW ;
Ellegren, H .
GENOME RESEARCH, 2005, 15 (01) :120-125
[4]   Male-biased mutation rate and divergence in autosomal, Z-linked and W-linked introns of chicken and turkey [J].
Axelsson, E ;
Smith, NGC ;
Sundström, H ;
Berlin, S ;
Ellegren, H .
MOLECULAR BIOLOGY AND EVOLUTION, 2004, 21 (08) :1538-1547
[5]  
Bielawski JP, 2000, GENETICS, V156, P1299
[6]   Sperm mobility determines the outcome of sperm competition in the domestic fowl [J].
Birkhead, TR ;
Martínez, JG ;
Burke, T ;
Froman, DP .
PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES, 1999, 266 (1430) :1759-1764
[7]   Dynamics of a human interparalog gene conversion hotspot [J].
Bosch, E ;
Hurles, ME ;
Navarro, A ;
Jobling, MA .
GENOME RESEARCH, 2004, 14 (05) :835-844
[8]   Multiple, polymorphic copies of SRY in both males and females of the vole Microtus cabrerae [J].
Bullejos, M ;
Sánchez, A ;
Burgos, M ;
Hera, C ;
Jiménez, R ;
de la Guardia, RD .
CYTOGENETICS AND CELL GENETICS, 1997, 79 (3-4) :167-171
[9]   Adaptive molecular evolution of HINTW, a female-specific gene in birds [J].
Ceplitis, H ;
Ellegren, H .
MOLECULAR BIOLOGY AND EVOLUTION, 2004, 21 (02) :249-254
[10]   Similar rates but different modes of sequence evolution in introns and at exonic silent sites in rodents: Evidence for selectively driven codon usage [J].
Chamary, JV ;
Hurst, LD .
MOLECULAR BIOLOGY AND EVOLUTION, 2004, 21 (06) :1014-1023