Department of Biochemistry and Immunology, Federal University of Minas Gerais, Belo Horizonte/MG, 31270-901, Brazil.
Department of Zoology, Federal University of Minas Gerais, Belo Horizonte/MG, 31270-901, Brazil.
Genes (Basel). 2010 Oct 20;1(3):357-70. doi: 10.3390/genes1030357.
Introns are common among all eukaryotes, while only a limited number of introns are found in prokaryotes. Globin and globin-like proteins are widely distributed in nature, being found even in prokaryotes and a wide range of patterns of intron-exon have been reported in several eukaryotic globin genes. Globin genes in invertebrates show considerable variation in the positions of introns; globins can be found without introns, with only one intron or with three introns in different positions. In this work we analyzed the introns in the myoglobin gene from Biomphalaria glabrata, B. straminea and B. tenagophila. In the Biomphalaria genus, the myoglobin gene has three introns; these were amplified by PCR and analyzed by PCR-RFLP. Results showed that the size (number or nucleotides) and the nucleotide sequence of the coding gene of the myoglobin are variable in the three species. We observed the presence of size polymorphisms in intron 2 and 3; this characterizes a homozygous/heterozygous profile and it indicates the existence of two alleles which are different in size in each species of Biomphalaria. This polymorphism could be explored for specific identification of Biomphalaria individuals.
内含子在所有真核生物中都很常见，而原核生物中只发现了有限数量的内含子。球蛋白和类球蛋白蛋白广泛存在于自然界中，甚至在原核生物中也有发现，并且在几个真核球蛋白基因中已经报道了多种内含子-外显子的模式。无脊椎动物的球蛋白基因在内含子位置上存在很大的差异；球蛋白可以没有内含子，只有一个内含子，也可以在不同位置有三个内含子。在这项工作中，我们分析了玻利维亚圆口螺（Biomphalaria glabrata）、巴西圆口螺（B. straminea）和多斑圆口螺（B. tenagophila）的肌红蛋白基因中的内含子。在玻利维亚螺属中，肌红蛋白基因有三个内含子；这些内含子通过 PCR 扩增，并通过 PCR-RFLP 进行分析。结果表明，在这三个物种中，肌红蛋白的大小（核苷酸数）和编码基因的核苷酸序列是可变的。我们观察到内含子 2 和 3 存在大小多态性；这表现出纯合子/杂合子的特征，并表明在每个玻利维亚螺物种中存在大小不同的两个等位基因。这种多态性可以用于玻利维亚螺个体的特异性鉴定。
