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Unusual conservation among genes encoding small secreted salivary gland proteins from a gall midge.
BMC Evol Biol. 2010 Sep 28; 10:296.BE

Abstract

BACKGROUND

In most protein-coding genes, greater sequence variation is observed in noncoding regions (introns and untranslated regions) than in coding regions due to selective constraints. During characterization of genes and transcripts encoding small secreted salivary gland proteins (SSSGPs) from the Hessian fly, we found exactly the opposite pattern of conservation in several families of genes: the non-coding regions were highly conserved, but the coding regions were highly variable.

RESULTS

Seven genes from the SSSGP-1 family are clustered as one inverted and six tandem repeats within a 15 kb region of the genome. Except for SSSGP-1A2, a gene that encodes a protein identical to that encoded by SSSGP-1A1, the other six genes consist of a highly diversified, mature protein-coding region as well as highly conserved regions including the promoter, 5'- and 3'-UTRs, a signal peptide coding region, and an intron. This unusual pattern of highly diversified coding regions coupled with highly conserved regions in the rest of the gene was also observed in several other groups of SSSGP-encoding genes or cDNAs. The unusual conservation pattern was also found in some of the SSSGP cDNAs from the Asian rice gall midge, but not from the orange wheat blossom midge. Strong positive selection was one of the forces driving for diversification whereas concerted homogenization was likely a mechanism for sequence conservation.

CONCLUSION

Rapid diversification in mature SSSGPs suggests that the genes are under selection pressure for functional adaptation. The conservation in the noncoding regions of these genes including introns also suggested potential mechanisms for sequence homogenization that are not yet fully understood. This report should be useful for future studies on genetic mechanisms involved in evolution and functional adaptation of parasite genes.

Authors+Show Affiliations

USDA-ARS, Hard Winter Wheat Genetics Research Unit, 4008 Throckmorton Hall, Kansas State University, Manhattan, KS 66506, USA. ming-shun.chen@ars.usda.govNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

20920202

Citation

Chen, Ming-Shun, et al. "Unusual Conservation Among Genes Encoding Small Secreted Salivary Gland Proteins From a Gall Midge." BMC Evolutionary Biology, vol. 10, 2010, p. 296.
Chen MS, Liu X, Yang Z, et al. Unusual conservation among genes encoding small secreted salivary gland proteins from a gall midge. BMC Evol Biol. 2010;10:296.
Chen, M. S., Liu, X., Yang, Z., Zhao, H., Shukle, R. H., Stuart, J. J., & Hulbert, S. (2010). Unusual conservation among genes encoding small secreted salivary gland proteins from a gall midge. BMC Evolutionary Biology, 10, 296. https://doi.org/10.1186/1471-2148-10-296
Chen MS, et al. Unusual Conservation Among Genes Encoding Small Secreted Salivary Gland Proteins From a Gall Midge. BMC Evol Biol. 2010 Sep 28;10:296. PubMed PMID: 20920202.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Unusual conservation among genes encoding small secreted salivary gland proteins from a gall midge. AU - Chen,Ming-Shun, AU - Liu,Xuming, AU - Yang,Ziheng, AU - Zhao,Huixian, AU - Shukle,Richard H, AU - Stuart,Jeffrey J, AU - Hulbert,Scot, Y1 - 2010/09/28/ PY - 2010/05/17/received PY - 2010/09/28/accepted PY - 2010/10/6/entrez PY - 2010/10/6/pubmed PY - 2010/12/24/medline SP - 296 EP - 296 JF - BMC evolutionary biology JO - BMC Evol Biol VL - 10 N2 - BACKGROUND: In most protein-coding genes, greater sequence variation is observed in noncoding regions (introns and untranslated regions) than in coding regions due to selective constraints. During characterization of genes and transcripts encoding small secreted salivary gland proteins (SSSGPs) from the Hessian fly, we found exactly the opposite pattern of conservation in several families of genes: the non-coding regions were highly conserved, but the coding regions were highly variable. RESULTS: Seven genes from the SSSGP-1 family are clustered as one inverted and six tandem repeats within a 15 kb region of the genome. Except for SSSGP-1A2, a gene that encodes a protein identical to that encoded by SSSGP-1A1, the other six genes consist of a highly diversified, mature protein-coding region as well as highly conserved regions including the promoter, 5'- and 3'-UTRs, a signal peptide coding region, and an intron. This unusual pattern of highly diversified coding regions coupled with highly conserved regions in the rest of the gene was also observed in several other groups of SSSGP-encoding genes or cDNAs. The unusual conservation pattern was also found in some of the SSSGP cDNAs from the Asian rice gall midge, but not from the orange wheat blossom midge. Strong positive selection was one of the forces driving for diversification whereas concerted homogenization was likely a mechanism for sequence conservation. CONCLUSION: Rapid diversification in mature SSSGPs suggests that the genes are under selection pressure for functional adaptation. The conservation in the noncoding regions of these genes including introns also suggested potential mechanisms for sequence homogenization that are not yet fully understood. This report should be useful for future studies on genetic mechanisms involved in evolution and functional adaptation of parasite genes. SN - 1471-2148 UR - https://www.unboundmedicine.com/medline/citation/20920202/Unusual_conservation_among_genes_encoding_small_secreted_salivary_gland_proteins_from_a_gall_midge_ L2 - https://bmcevolbiol.biomedcentral.com/articles/10.1186/1471-2148-10-296 DB - PRIME DP - Unbound Medicine ER -