A salmon id phylogeny inferred from mitochondrial cytochrome b gene sequences

Partial mitochondrial cytochrome b gene sequences of eight salmonid species were used in a PAUP analysis to generate a phylogeny of the group. The four genera represented are Salmo, Salvelinus, Oncorhynchus and Thymallus . The inferred phylogenetic tree coincides well with the classically derived one for these genera. The recent reclassification of the rainbow trout as a member of the genus Oncorhynchus is supported. The assignment of grayling as the outgroup is vindicated. The utility of gene sequence data to infer the phylogenetic relationships of the Salmonidae is discussed.     

Phylogenetic relationships of glyptosternoid fishes (Siluriformes: Sisoridae) inferred from mitochondrial cytochrome b gene sequences

To explore phylogenetic relationships among glyptosternoid fishes, we determined nucleotide sequences of the complete mitochondrial cytochrome b gene region (1138 base pair). Thirteen species of glyptosternoid fishes and six species of non-glyptosternoids represent 10 sisorid genera were examined. Molecular phylogenetic trees were constructed using the maximum parsimony, minimum evolution, maximum likelihood, and Bayesian methods. Bayesian and maximum likelihood analyses support the monophyly of glyptosternoids, but our hypothesis of internal relationships differs from previous hypothesis. Results indicated that glyptosternoid is a monophyletic group and genera Glyptosternum and Exostoma are two basal species having a primitive position among it. Genera Euchiloglanis and Pareuchiloglanis form a sister-group. Then they form a sister-group with Pseudexostoma plus Oreoglanis. Our result also found that Pareuchiloglanis anteanalis might be considered as the synonyms of Parechiloglanis sinensis, and genus Euchiloglanis might have only one valid species, Euchiloglanis davidi.     

Phylogenetic relationships among Nearctic shrews of the genus Sorex (Insectivora, Soricidae) inferred from combined cytochrome b and inter-SINE fingerprint data using Bayesian analysis

The field of molecular systematics has relied heavily on mitochondrial DNA (mtDNA) analysis since its inception. Despite the obvious utility of mtDNA, such data inevitably only presents a limited (i.e., single genome) perspective on species evolution. A combination of mitochondrial and nuclear markers is essential for reconstructing more robust phylogenetic trees. To evaluate the utility of one category of nuclear marker (short interspersed elements or SINEs) for resolving phylogenetic relationships, we constructed an inter-SINE fingerprint for nine putative species of the genus Sorex. In addition, we analyzed 1011 nucleotides of the cytochrome b gene. Traditional neighbor-joining and maximum parsimony analyses were applied to the individual cytochrome b and inter-SINE fingerprint data sets, along with Bayesian analysis to the combined data sets. We found inter-SINE fingerprinting to be an effective species level marker; however, we were unable to reconstruct deeper branching patterns within the Sorex genus using these data. The combined data analyzed under a Bayesian analysis showed higher levels of structuring within the Otisorex subgenus, most notably recognizing a monophyletic group consisting of sister-taxa S. palustris and S. monticolus, S. cinereus and S. haydeni, and S. hoyi. An additional noteworthy result was the detection of an historic mitochondrial introgression event between S. monticolus and S. palustris. When combining disparate data sets, we emphasize researcher diligence as certain types of data and processes may overly influence the analysis. However, there is considerable phylogenetic potential stemming from inter-SINE fingerprinting.     

Phylogenetic relationships among bumble bees (Bombus, latreille) inferred from mitochondrial cytochrome b and cytochrome oxidase I sequences

We conducted a molecular study intending to derive an estimate of the relationships within the genus Bombus (bumble bees) by comparing the mitochondrial cytochrome b and cytochrome oxidase I (COI) genes from 19 species, spanning 10 of approximately 16 European subgenera and 3 subgenera from North and South America. Our trees differ from the most recent classifications of bumble bees. Although bootstrap values for deep branches are low, our sequences show significant data structure and low homoplasy, and all trees share some groups and patterns. In all cases, the subgenus Bombus s. str. clusters among the most derived bumble bees, contrary to other molecular studies. In all trees, B. funebris is the sister taxon of B. robustus, and in five of the six trees, B. wurflenii is the sister taxon to this clade. B. nevadensis is basal to the other species in the analysis of the cytochrome b gene, but appears to be among the most derived according to the analysis of the COI region. The species representing the subgenera Thoracobombus and Fervidobombus are consistently among the earliest diverged. Species that appear in very different positions in different trees are B. nevadensis, B. mesomelas, B. balteatus, and B. hyperboreus. All subgenera with two representatives in our analysis are apparently monophyletic except Fervidobombus, Melanobombus, and Pyrobombus. The groups formed by pocket makers and non-pocket makers within Bombus also appear to be paraphyletic, and therefore some subgenera may not accurately reflect phylogeny.     

Phylogenetic divergence in leatherside chub (Gila copei) inferred from mitochondrial cytochrome b sequences

We examined intra-specific phylogenetic relationships in leatherside chub, Gila copei. The complete mitochondrial (mt) cytochrome b gene (1140 bp) was sequenced for 30 individuals from 10 populations that span the geographical distribution of this species. Traditional phylogenetic analyses revealed two deeply divergent and evolutionarily distinct mtDNA clades that are geographically separated in northern and southern drainage basins. Interpopulation sequence variation between clades ranged from 7.7 to 8.1%. The northern clade was genetically more similar and phylogenetically more closely related to the selected out-group Lepidomeda m. mollispinus than to the southern clade, suggesting that the taxonomy of this species may require revision. Sequence variation among populations within clades ranged from 0 to 0.3% in the north and from 0 to 0.7% in the south. Statistical parsimony was used to construct phylogenetic networks of haplotypes within clades. Nested clade analysis revealed that geographical fragmentation has played an important role in genetic structuring within northern and southern clades.     

Phylogeny of the genus Chironomus (Diptera) inferred from DNA sequences of mitochondrial cytochrome b and cytochrome oxidase I

Two mitochondrial genes, Cytochrome b (Cytb) and Cytochrome c oxidase subunit I (COI), have been used as phylogenetic markers in Chironomids. The nucleotide sequences of 685 bp from Cytb and 596 bp from COI have been determined for 36 Chironomus species from the Palearctic, or Holarctic, and Australasia. The concatenated sequence of 1281 bp from both genes was used to investigate the phylogenetic relationships among these species. The nucleotide sequence alignments were used for construction of phylogenetic trees based on maximum-parsimony and neighbor-joining methods. Both techniques produced similar phylogenies. Monophyly of the genus Chironomus is supported by a bootstrap value of 100% at the basal branch. Six clusters of species have been revealed with high bootstrap values supporting both monophyly of each cluster and the validity of the branching order within each cluster. Four species, C. circumdatus, C. nepeanensis, C. dorsalis, and C. crassiforceps, cannot be placed into any cluster. Cytological phylogenies were constructed using the same set of species, except for C. biwaprimus. These trees showed many similarities to that obtained from the mitochondrial (mt) sequence analysis, but also a number of significant differences. When compared with the tree constructed from the sequence of 23 species available for one of the globin genes, globin 2b (gb2b), there was better support for the mt tree than for the cytological trees. An intron, which varies in its occurrence and position in gb2b, was also investigated and the distribution of the introns supports the phylogenetic history of the genus Chironomus obtained with mt data. The differences observed in the cytological trees seem to be attributable more to the retention of the same chromosome banding sequence across several species, rather than convergent evolutionary events. An important question is the determination of the position of the subgenus Camptochironomus in relation to the representatives of the nominal subgenus Chironomus, since it has been suggested that this is a separate genus. The Camptochironomus species are internal to the trees and have arisen more recently than some of the species of the subgenus Chironomus, indicating that they are not sufficiently differentiated to be considered more than a subgenus.     

Phylogenetic relationships of four species of floating gobies (Gymnogobius) as inferred from partial mitochondrial cytochrome b gene sequences

 To clarify the intra- and interspecific relationships of four Gymnogobius species, G. urotaenia, G. isaza, Gymnogobius sp. 1 (sumiukigori), and Gymnogobius sp. 2 (shimaukigori), partial mitochondrial cytochrome b gene sequences of 639 bp were obtained for a total of 31 specimens from Japan and Korea, plus 2 outgroup specimens. Twenty-nine haplotypes were identified in the ingroup, with a total of 122 variable sites (19.1%). The individuals regarded as the same species morphologically were monophyletic genetically. Sequence differences between amphidromous individuals of three species distributed in both Japan and Korea were relatively small (0.16–1.25%). The largest intraspecific sequence difference was observed between individuals of G. urotaenia from Lake Biwa and those from other localities (1.25–2.19%). Interspecific sequence differences ranged from 4.07% to 13.46%; neighbor-joining, maximum-parsimony, and maximum-likelihood methods indicated that Gymnogobius sp. 2 diverged first, followed by G. isaza, with Gymnogobius sp. 1 and G. urotaenia being monophyletic. The estimated divergence time of each species, based on estimated divergence rates for mitochondrial protein-coding genes already reported (0.8–2.8%/my), suggested that speciation occurred mainly in the Pliocene (possibly Miocene), with G. isaza (a Lake Biwa endemic) diverging significantly earlier (probably Lake Kouga stage) than estimated in previous studies. In contrast, according to the previous hypothesis, the substitution rates were highly overestimated to about 12–20%/my. Received: November 19, 2001 / Revised: May 20, 2002 / Accepted: June 18, 2002 Acknowledgments Special thanks are due to Katsutoshi Watanabe and Yuji Yamazaki for valuable advice and providing fish samples. We also thank Kouji Nakayama, Toshiyuki Ohkawa, Motoomi Yamaguchi, and members of the Laboratory of Marine Biology, Fukui Prefectural University, and members of the Laboratory of Molecular Marine Biology, Ocean Research Institute, University of Tokyo, and the Laboratory of Marine Stock Enhancement, University of Kyoto, for their help and advice during the present study. Correspondence to:Shigeo Harada     

Population genetic structure of Sorex unguiculatus and Sorex caecutiens (Soricidae, Mammalia) in Hokkaido, based on microsatellite DNA polymorphism

We investigated the genetic structure of Sorex unguiculatus and Sorex caecutiens populations in Hokkaido, Japan, using hypervariable microsatellite DNA markers. We used five microsatellite loci to type 475 S. unguiculatus individuals from 20 localities on the Hokkaido mainland and four localities from each of four offshore islands (and 11 shrews from one locality in southern Sakhalin for a particular analysis). We used six microsatellite loci to type 240 S. caecutiens individuals from 13 localities on the Hokkaido mainland. Genetic variation was high in mainland populations of both species and low in the island populations of S. unguiculatus. Allelic richness and island size were positively correlated for S. unguiculatus, suggesting that genetic drift occurred on those islands due to small population size. In addition, four insular populations of S. unguiculatus were genetically differentiated from the mainland populations, although clear phylogeographic clustering was not confirmed among populations on the Hokkaido mainland for either S. unguiculatus or S. caecutiens. Heterozygosity excess was observed in more than half of the populations including the mainland populations of the two species, suggesting recent bottleneck events in these populations. Population dynamics of the shrews might be explained by a metapopulation scheme. According to autocorrelation analysis, the extent of non-random spatial genetic structure was approximately 100 km. Isolation by distance was observed in S. unguiculatus, but not in S. caecutiens although there is a positive trend. The lack of correlation for S. caecutiens might have been due to small sample size. Thus, no obvious differences in population genetic structure were found between the two species on the Hokkaido mainland in the present study, while previous investigations using mitochondrial DNA sequences inferred that these two species might have rather different biogeographic histories.     

Phylogeography of Altai osmans fishes (Oreoleuciscus sp., Cyprinidae, Pisces) inferred from nucleotide variation of the mitochondrial DNA cytochrome b gene

In this study, analyses based on cytochrome b gene (Cyt-b) mtDNA sequences were undertaken to clarify phylogenetic and phylogeographical relationships among populations Oreoleuciscus sp. (Pisces: Cyprinidae) from Western Mongolia. Two major clusters, designated clusters A and B, and minor clusters were discriminated. Cluster A comprised specimens of Oreoleuciscus from the Valley of Lakes. The cluster B consists of two subclusters; one of them (B1) including populations Oreoleuciscus of the Hollow of the Big Lakes and lakes Big Altai Range. Second subclusters (B2) combines specimens of Oreoleuciscus from Hollow of the Lake Uvs, some isolated lakes of the North-Western Khangay and waterbodies of the Arctic Ocean Basin (Selenge and Orchon basins). On the basis of estimations of sizes genetic and time of a divergence of the revealed genetikal-geographical groups existence of three allopatric species of the within genera Oreoleuciscus is proved.     

Molecular phylogeny and biogeography of woolly flying squirrel (Rodentia: Sciuridae), inferred from mitochondrial cytochrome b gene sequences

To investigate the genetic diversity between the populations of woolly flying squirrels (Eupetaurus) from the eastern and western extremes of the Himalayas, partial mitochondrial cytochrome b gene sequences (390-810 bp) that were determined from the museum specimens were analyzed using maximum parsimony (MP) and maximum likelihood (ML) methods. The molecular data reveal that the two specimens that were collected in northwestern Yunnan (China) are members of the genus Eupetaurus. Reconstructed phylogenetic relationships show that the populations of Eupetaurus in the eastern and western extremes of the Himalayas are two distinct species with significant genetic differences (12%) and diverged about 10.8 million years ago. Eupetaurus is significantly different from Petaurista and Pteromys. The level of estimated pairwise-sequence divergence observed between Eupetaurus and Petaurista or Pteromys is greater than that observed between Eupetaurus and Trogopterus, Belomys, Glaucomys, or Hylopetes. Considering the divergence time of the two Eupetaurus groups, the glaciations and the uplift of the Himalayas and Qinghai-Tibet plateau during the Pliocene-Pleistocene period might be the major factors affecting the present distribution of Eupetaurus along the Himalayas.     

Phylogenetic relationships among four species of Mullidae (Perciformes) inferred from DNA sequences of mitochondrial cytochrome b and 16S rRNA genes

DNA sequence comparisons of two mitochondrial DNA genes were used to infer phylogenetic relationships among four species of mullids. Approximately 238 bp of the mitochondrial 16S ribosomal RNA (rRNA) and 261 bp of the cytochrome b (cytb) genes were sequenced from representatives of three mullid genera (Mullus, Upeneus, Pseudopeneus), present in the Mediterranean Sea. Trees were constructed using three methods: maximum likelihood (ML), neighbor joining (NJ) and parsimony (MP). The results of the analyses of these data together with published data of the same mtDNA segments of two other perciform species (Sparus aurata, Perca fluviatilis), support the previous taxonomic classification of the three genera examined, as well as the classification of the two red mullet species in the same genus.     

Molecular phylogeny of the chipmunks inferred from Mitochondrial cytochrome b and cytochrome oxidase II gene sequences

There are currently 25 recognized species of the chipmunk genus Tamias. In this study we sequenced the complete mitochondrial cytochrome b (cyt b) gene of 23 Tamias species. We analyzed the cyt b sequence and then analyzed a combined data set of cyt b along with a previous data set of cytochrome oxidase subunit II (COII) sequence. Maximum-likelihood was used to further test the fit of models of evolution to the cyt b data. Other sciurid cyt b sequence was added to examine the evolution of Tamias in the context of other sciurids. Relationships among Tamias species are discussed, particularly the possibility of a current sorting event among taxa of the southwestern United States and the extreme divergences among the three subgenera (Neotamias, Eutamias, and Tamias).     

Molecular phylogeny of songbirds (Passeriformes) inferred from mitochondrial 16S ribosomal RNA gene sequences

Phylogenetic relationships among the families of passerine birds have been the subject of many debates. These relationships have been investigated by using a number of different character sets, including morphology, proteins, DNA-DNA hybridization, and mitochondrial DNA gene sequences. Our objective was to examine the phylogenetic relationships of a set of passerine songbirds (Oscines) and to test the taxonomic relationships proposed by. We sequenced 1403 aligned bases encompassing the mitochondrial transfer-RNA-Valine and 16S ribosomal RNA genes in 27 species from 14 families (including a Suboscine outgroup). Our results differ in significant ways from the superfamily designations of Sibley and Ahlquist by questioning the monophyly of the Sylvioidea and by placing the Regulidae in the Corvoidea.     

Phylogeny of the eelpout genus Lycodes (Pisces,Zoarcidae) as inferred from mitochondrial cytochrome b and 12S rDNA

The bottom-dwelling and species-rich eelpout genus Lycodes Reinhardt has a great potential for the study of Arctic marine speciation. Subdivision of the genus has been based on single or few morphological characters (e.g., lateral line configuration) with contradicting results and phylogenetic approaches have not been attended. Here we present the first phylogenetic analysis of the genus employing DNA sequences of the mitochondrial genes cytochrome b and 12S rDNA (714 bp). The analysis with the two genes combined resulted in two equally parsimonious trees. In both cladograms most of the previously suggested subgroups are para- or polyphyletic, except for the so-called short-tailed Lycodes spp., with a short tail, a single mediolateral lateral line configuration and a shallow or filled otolith sulcus. The group of long-tailed Lycodes spp., with ventral or ventro-medio-lateral types of lateral line configuration and a deep otolith sulcus, appears to be paraphyletic, since Pacific and Atlantic species in this group are not each other's closest relatives. Thus, the short-tailed species are placed in a derived clade, indicating a secondary shortening of the tail, and a "slope to shore" type of evolution. This is not in accordance with earlier assumptions of the more elongate, deeper living species being the more derived. The basal position of long-tailed Pacific species supports earlier theories of Pacific origin of the genus/family. Small genetic differences between Arctic/Atlantic species indicate a rather recent radiation in these areas after the opening of the Bering Strait 3.0-3.5 million years ago.     

Evolutionary relationships among narrow-headed rats (genus Stenocephalemys, Muridae, Rodentia) inferred from complete cytochrome b gene sequences

Using the data on complete sequences of cytochrome b gene, phylogenetic relationships were studied among the Stenocephalemys s. lat. (Stenocephalemys ssp. + Praomys albipes) murine rodents, inhabiting adjacent altitudinal belts of the isolated Ethiopian mountain massifs, and among the related Praomys s. lat. species. Extremely low resolution of the relationships among the main Praomys s. lat. lineages hampered identification of the nearest sister group for the Stenocephalemys s. lat. "Ethiopian" clade, monophyly of which was strongly supported. Sister relationships between P. albipes and S. griseicauda (implying "accelerated" morphological and chromosomal evolution upon the formation of the former species), as well as between S. albocaudata and the recently described novel chromosomal form of Stenocephalemus sp. A (2n = 50; NFa = 56) were demonstrated. Definite discordance between the rates of their molecular, chromosomal, and morphological evolution was revealed. Based on phylogenetic reconstructions and the estimates of the divergence time, obtained by use of molecular clock method, an attempt to draw a phylogenetic scenario for the group examined was made. The obtained data were compared to those for analogous Sigmodontinae species complexes, distributed across a marked altitudinal gradient on the Andean slopes. It was shown that molecular genetic data on the rodents from mountain tropics did not support the gradient model of diversification, based on the possibility of morphological diversification prior to their achievement of the species status (without interruption of the gene flow between the forms) due to differently directed selection across a strong environmental gradient.     

Evolutionary relationships among narrow-headed rats (genus Stenocephalemys, muridae, rodentia) inferred from complete cytochrome b gene sequences

Using the data on complete sequences of cytochrome b gene, phylogenetic relationships were studied among the Stenocephalemys s. lat. (Stenocephalemys spp. + Praomys albipes) murine rodents, inhabiting adjacent altitudinal belts of the isolated Ethiopian mountain massifs, and among the related Praomys s. lat. species. Extremely low resolution of the relationships among the main Praomys s. lat. lineages hampered identification of the nearest sister group for the Stenocephalemys s. lat. “Ethiopian” clade, monophyly of which was strongly supported. Sister relationships between P. albipes and S. griseicauda (implying “accelerated” morphological and chromosomal evolution upon the formation of the former species), as well as between S. albocaudata and the recently described novel chromosomal form of Stenocephalemus sp. A (2n = 50; NFa = 56) were demonstrated. Definite discordance between the rates of their molecular, chromosomal, and morphological evolution was revealed. Based on phylogenetic reconstructions and the estimates of the divergence time, obtained by use of molecular clock method, an attempt to draw an evolutionary scenario for the group examined was made. The obtained data were compared to those for Sigmodontinae species complexes, distributed across a marked altitudinal gradient on the Andean slopes. It was shown that molecular genetic data on the rodents from mountain tropics did not support the gradient model of diversification, based on the possibility of diversification of the forms up to their achievement of the species rank (without interruption of the gene flow between them) due to differently directed selection across a strong environmental gradient.     

Density-Dependent Behavior of Shrews (Sorex araneus, S. caecutiens, and S. minutus) under Natural and Experimental Conditions

The behavior of three common shrew species was compared in a test of pairwise placement in a neutral territory (10 min) for various population densities in natural habitats and for animals kept isolated or in groups in open-air cages. The behavior of the animals captured in nature was regarded as the norm. We analyzed the total number of social contacts (as an index of social activity), as well as the frequencies of direct and ritualized aggressive interactions, rejection of contacts, and friendly interactions (as parameters characterizing the structure of interactions). Isolation of the shrews proved to decrease their social activity. The highest frequency of interactions was observed in the animals kept in groups in open-air cages. The level of sociality and changes in behavior related to differences in population density in the three shrew species can be more significant than the species-specific differences in their behavior.     

Molecular phylogenetics of soricid shrews (Mammalia) based on mitochondrial cytochrome b gene sequences: with special reference to the Soricinae

Molecular phylogeny of soricid shrews (Soricidae, Eulipotyphla, Mammalia) based on 1140 bp mitochondrial cytochrome b gene (cyt b ) sequences was inferred by the maximum likelihood (ML) method. All 13 genera of extant Soricinae and two genera of Crocidurinae were included in the analyses. Anourosorex was phylogenetically distant from the main groupings within Soricinae and Crocidurinae in the ML tree. Thus, it could not be determined to which subfamily Anourosorex should be assigned: Soricinae, Crocidurinae or a new subfamily. Soricinae (excluding Anourosorex ) should be divided into four tribes: Neomyini, Notiosoricini, Soricini and Blarinini. However, monophyly of Blarinini was not robust in the present data set. Also, branching orders among tribes of Soricinae and those among genera of Neomyini could not be determined because of insufficient phylogenetic information of the cyt b sequences. For water shrews of Neomyini ( Chimarrogale , Nectogale and Neomys ), monophyly of Neomys and the Chimarrogale – Nectogale group could not be verified, which implies the possibility of multiple origins for the semi-aquatic mode of living among taxa within Neomyini. Episoriculus may contain several separate genera. Blarinella was included in Blarinini not Soricini, based on the cyt b sequences, but the confidence level was rather low; hence more phylogenetic information is needed to determine its phylogenetic position. Furthermore, some specific problems of taxonomy of soricid shrews were clarified, for example phylogeny of local populations of Notiosorex crawfordi , Chimarrogale himalayica and Crocidura attenuata .     

New insights into the taxonomy and phylogeny of social voles inferred from mitochondrial cytochrome b sequences

We sequenced the entire cytochrome b gene in Microtus paradoxus from Turkmenistan and Microtus socialis from Crimea and Kalmykia. Phylogenetic relationships among social voles were reconstructed by the inclusion into analyses of a further 23 published haplotypes belonging to six species. The two probabilistic methods which were used in phylogenetic analyses, the Bayesian inference and Maximum Likelihood, yielded very similar results. Both trees showed two highly divergent lineages which were further subdivided into seven species. The socialis lineage encompassed four species (M. socialis, M. irani, M. anatolicus, and M. paradoxus), and the remaining three species clustered into the guentheri lineage (M. guentheri, M. hartingi, M. dogramacii). The ranges for nucleotide divergences between seven species of social voles (4.95–9.28% and 4.18–8.81% for mean and net divergences, respectively) mainly exceeded 4.3%, which is frequently regarded as the conservative cut-off between sibling species in the specious genus Microtus.     

从细胞色素b基因全序列探讨大额牛的分子系统发生

大额牛是一种半野生半家养的珍稀牛种, 有关其起源和系统地位一直存在争议。通过PCR扩增、测序等步骤共获得了11头大额牛细胞色素b(Cyt b)基因全序列(1 140 bp)。应用分析软件, 对大额牛11条Cyt b序列进行了分析, 并结合GenBank中牛属动物6个近缘种的同源序列, 以亚洲水牛(Bubalus bubalis)为外群, 分别采用邻接法(NJ)和最大简约法(MP)构建了牛属动物分子系统发育树。序列分析结果表明, 11条大额牛Cyt b序列1 140位点中, 共发现95个变异位点(占分析位点总数的8.33 %), 定义了6种单倍型, 表明大额牛群体的Cyt b基因遗传多态性比较丰富。构建的NJ和MP分子系统树均显示, 大额牛研究群体明显分为3支, 第1支与普通牛(Bos taurus)相聚, 第2支与瘤牛(Bos indicus)相聚, 第3支与印度野牛(Bos gaurus)相聚。系统发育分析表明, 大额牛很可能是印度野牛的家养型或驯化种, 我国大额牛群体可能曾受到其他牛种血缘的入侵。