열수 장님게의 미토콘드리아 위유전자가 바코드 연구에 미치는 영향

Abstract

Members of the brachyuran crab family, Bythograeidae, are among the most abundant and common crabs in vent fields. However, their identification based on morphological characteristics often leads to incorrect species recognition due to a lack of taxonomic factors and the existence of sibling (or cryptic) species. For these reasons, we used DNA barcoding for vent crabs using mitochondrial cytochrome c oxidase subunit 1 (CO1). However, several nuclear mitochondrial pseudogenes (Numts) were amplified from Austinograea alayseae Guinot, 1990, using universal primers (Folmer primers). The Numts were characterized in six haplotypes, with 13.58&#8209 14.11% sequence divergence from Au. alayseae, a higher non-synonymous substitution ratio than true CO1, and the formation of an independent clade in bythograeids. In a neighbor-joining tree, the origin of the Numts would be expected to incorporate into the nucleus at an ancestral node of Austinograea, and they mutated more slowly in the nucleus than CO1 in the mitochondria. This evolutionary process may have resulted in the higher binding affinity of Numts for the Folmer primers than CO1. In the present study, we performed long PCR for the amplification of CO1 in Au. alayseae. We also present evidence that Numts can introduce serious ambiguity into DNA barcoding, including overestimating the number of species in bythograeids. These results may help a lack of taxonomic factors and the existence of sibling (or cryptic) species. For these reasons, we used DNA barcoding for vent crabs using mitochondrial cytochrome c oxidase subunit 1 (CO1). However, several nuclear mitochondrial pseudogenes (Numts) were amplified from Austinograea alayseae Guinot, 1990, using universal primers (Folmer primers). The Numts were characterized in six haplotypes, with 13.58&#8209 14.11% sequence divergence from Au. alayseae, a higher non-synonymous substitution ratio than true CO1, and the formation of an independent clade in bythograeids. In a neighbor-joining tree, the origin of the Numts would be expected to incorporate into the nucleus at an ancestral node of Austinograea, and they mutated more slowly in the nucleus than CO1 in the mitochondria. This evolutionary process may have resulted in the higher binding affinity of Numts for the Folmer primers than CO1. In the present study, we performed long PCR for the amplification of CO1 in Au. alayseae. We also present evidence that Numts can introduce serious ambiguity into DNA barcoding, including overestimating the number of species in bythograeids. These results may help