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Synonymous single nucleotide polymorphism in arsenic (+3) methyltransferase of the Western mosquitofish (Gambusia affinis) and its gene expression among field populations
被引:3
|作者:
Park, Daesik
[1
]
Propper, Catherine R.
[2
]
Wang, Guangning
[2
]
Salanga, Matthew C.
[2
]
机构:
[1] Kangwon Natl Univ, Div Sci Educ, Chunchon 24341, Kangwon, South Korea
[2] No Arizona Univ, Dept Biol Sci, Box 5640, Flagstaff, AZ 86011 USA
基金:
美国国家卫生研究院;
关键词:
Arsenic;
as3mt;
Cyt19;
mosquitofish;
Gambusia affinis;
Arizona;
AS3MT;
EXPOSURE;
IDENTIFICATION;
METHYLATION;
ADAPTATION;
D O I:
10.1007/s10646-021-02376-8
中图分类号:
Q14 [生态学(生物生态学)];
学科分类号:
071012 ;
0713 ;
摘要:
Naturally occurring arsenic is toxic at extremely low concentrations, yet some species persist even in high arsenic environments. We wanted to test if these species show evidence of evolution associated with arsenic exposure. To do this, we compared allelic variation across 872 coding nucleotides of arsenic (+3) methyltransferase (as3mt) and whole fish as3mt gene expression from three field populations of Gambusia affinis, from water sources containing low (1.9 ppb), medium-low (3.3 ppb), and high (15.7 ppb) levels of arsenic. The high arsenic site exceeds the US EPA's Maximum Contamination Level for drinking water. Medium-low and high populations exhibited homozygosity, and no sequence variation across all animals sampled. Eleven of 24 fish examined (45.8%) in the low arsenic population harbored synonymous single nucleotide polymorphisms (SNPs) in exons 4 and/or 10. SNP presence in the low arsenic population was not associated with differences in as3mt transcript levels compared to fish from the medium-low site, where SNPs were noted; however, as3mt expression in fish from the high arsenic concentration site was significantly lower than the other two sites. Low sequence variation in fish populations from sites with medium-low and high arsenic concentrations suggests greater selective pressure on this allele, while higher variation in the low population suggests a relaxed selection. Our results suggest gene regulation associated with arsenic detoxification may play a more crucial role in influencing responses to arsenic than polymorphic gene sequence. Understanding microevolutionary processes to various contaminants require the evaluation of multiple populations across a wide range of pollution exposures.
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页码:711 / 718
页数:8
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