Genetic variation in plasma prealbumin of the house mouse.

Rate of electrophoretic migration of prealbumin-2 of mouse blood plasma was found to be controlled by three autosomal codominant alleles. Presence and absence of a component next to albumin (prealbumin-4) was shown to be controlled by autosomal dominant and recessive alleles, respectively, and to be affected by sex. Evidence was presented for close linkage of the Pre-2 and Pre-4 loci, and for the control of albumin conformation by a separate locus.     

Studies of mitochondrial DNA,allozyme and morphometric variation in a house mouse hybrid zone

An unusual chromosomal hybrid zone of the house mouse, Mus musculus domesticus, exists in Upper Valtellina, Northern Italy, consisting of four Robertsonian (Rb) races and the standard (all-acrocentric, or 2n = 40) race, all hybridizing freely within 10 km2. The hybrid zone in Valtellina provides an excellent opportunity to study the role of Rb fusions in reproductive isolation and speciation. This hybrid zone has already been well studied for the distribution of Rb fusions and the fertility of hybrids, but in order to understand the dynamics of the zone, a basic understanding of the origin and genetic similarity of the chromosomal races is necessary. This paper presents the results of three different methods of measuring genetic differentiation: multivariate analysis of morphological traits and analyses of allozyme variation and mitochondrial DNA sequences. The standard race is clearly distinguishable from the three Rb races by all three methods, but the Rb races are not distinguishable from one another. This provides strong evidence for our previous suggestions that the well-established Rb races in Valtellina are closely related, and that the standard race was introduced into the valley more recently from a distant source. The fact that the Rb races are indistinguishable is also consistent with our hypothesis that a within-village speciation event involving two of the races (Hauffe & Searle, 1992) was a recent occurrence. The low level of allozyme heterozygosity among the Rb races suggests that these populations are the products of at least one bottleneck. The present article substantially extends earlier studies and provides the first detailed morphological and molecular analysis of this complex hybrid zone.     

海南岛宽额鳢(Channa gachua)群体遗传变异与生物地理过程

为了解海南岛宽额鳢(Channa gachua)的群体遗传分化和亲缘生物地理过程,采集了云南元江和海南岛5个水系(昌化江、陵水河、藤桥河、万泉河及南渡江)共6个种群168个宽额鳢个体,基于线粒体细胞色素b(Cyt b)基因全序列(1142 bp)对其遗传多样性和遗传分化程度进行了评估,并探讨了地质和气候等因素如何塑造了这一物种的亲缘地理结构及演化历史。基于Cyt b序列构建的系统树结果将所有个体分成两个主要谱系(A和B),谱系A包括海南岛所有种群,其中,部分昌化江个体形成独立的亚支(A2),其余个体聚为另一亚支(A1),谱系B为云南元江的全部个体,各谱系间的遗传分化指数均较高。种群历史动态分析表明,各谱系均没有发生种群扩张,但A1亚支与谱系B曾在约1万年前发生过有效种群数量减小的事件。根据研究结果推测,更新世冰期期间,北部湾因海平面下降而暴露,大陆和海南岛的水系发生接触,越南北部水系(包括元江/红河)通过一条联系雷州半岛和海南岛的古河道流入南海,因而冰期期间宽额鳢有机会从元江(红河)扩散至海南岛西南部,随后在海南岛内部,宽额鳢进一步扩散,并以五指山为种群间基因交流的重要地理障碍,各水系间种群发生基因交流和遗传分化。     

Sheep mitochondrial DNA variation in European, Caucasian, and Central Asian areas

Three distinct mitochondrial maternal lineages (haplotype Groups A, B, and C) have been found in the domestic sheep. Group B has been observed primarily in European domestic sheep. The European mouflon carries this haplotype group. This could suggest that European mouflon was independently domesticated in Europe, although archaeological evidence supports sheep domestication in the central part of the Fertile Crescent. To investigate this question, we sequenced a highly variable segment of mitochondrial DNA (mtDNA) in 406 unrelated animals from 48 breeds or local varieties. They originated from a wide area spanning northern Europe and the Balkans to the Altay Mountains in south Siberia. The sample included a representative cross-section of sheep breeds from areas close to the postulated Near Eastern domestication center and breeds from more distant northern areas. Four (A, B, C, and D) highly diverged sheep lineages were observed in Caucasus, 3 (A, B and C) in Central Asia, and 2 (A and B) in the eastern fringe of Europe, which included the area north and west of the Black Sea and the Ural Mountains. Only one example of Group D was detected. The other haplotype groups demonstrated signs of population expansion. Sequence variation within the lineages implied Group A to have expanded first. This group was the most frequent type only in Caucasian and Central Asian breeds. Expansion of Group C appeared most recently. The expansion of Group B involving Caucasian sheep took place at nearly the same time as the expansion of Group A. Group B expansion for the eastern European area started approximately 3,000 years after the earliest inferred expansion. An independent European domestication of sheep is unlikely. The distribution of Group A variation as well as other results are compatible with the Near East being the domestication site. Groups C and D may have been introgressed later into a domestic stock, but larger samples are needed to infer their geographical origin. The results suggest that some mitochondrial lineages arrived in northern Europe from the Near East across Russia.     

Genetic diversity and phylogeography of Siberian roe deer,Caproulus pygargus,in central and peripheral populations

Current understanding of phylogeographical structure and genetic diversity of Siberian roe deer remains limited mainly due to small sample size and/or low geographical coverage in previous studies. Published data suggest at least two phylogroups: western (Ural Mountains and Western Siberia) and eastern (east from lake Baikal, including the Korean peninsula), but their phylogenetic relationship remains unclear. Combined sequences of cytochrome b (1140 bp) and the mtDNA control region (963 bp) were analyzed from 219 Siberian roe deer from 12 locations in Russia, Mongolia, and South Korea, which cover a large part of its range, to assess genetic diversity and phylogeographical status. Special emphasis was placed on the demographic history and genetic features of central, peripheral, and isolated populations. Results of median‐joining network and phylogenetic tree analyses indicate that Siberian roe deer from the Urals to the Pacific Ocean are genetically diverse and that geographical distribution and composition of haplogroups coincide with previously described ranges of the subspecies Capreolus pygargus pygargus and Capreolus pygargus tianschanicus. We found that peripheral populations in the northwestern parts of the species range (Urals), as well as the isolated population from Jeju Island, are genetically distinct from those in the core part of the range, both in terms of genetic diversity and quantitative composition of haplogroups. We also found that northwestern (Urals) and northern (Yakutia) peripheral populations share the same haplogroup and fall into the same phylogenetic clade with the isolated population from Jeju Island. This finding sheds light on the taxonomic status of the Jeju Island population and leads to hypotheses about the discordance of morphological and genetic evolution in isolated populations and specific genetic features of peripheral populations.     

Genetic signature of reproductive manipulation in the phylogeography of the bat fly, Trichobius major

The bat fly (Trichobius major) is a blood-feeding ectoparasite of the cave myotis (Myotis velifer). A recent mitochondrial DNA (mtDNA) study examining population structure of T. major in the South Central United States detected a single haplotype from all individuals examined (N = 48 from 12 different caves), representing one of only a few known examples of such widespread mtDNA uniformity. We examined nuclear genetic diversity using amplified fragment length polymorphism and detected high levels of nuclear genetic diversity in all populations sampled. Amplified fragment length polymorphism analyses indicated significant levels of gene flow among caves >700 km apart, suggesting the absence of mtDNA diversity in T. major is the result of a selective sweep, not a demographic event (i.e., a recent bottleneck). One mechanism by which mtDNA sweeps occur in arthropods is through bacterial parasites that manipulate host reproduction and mtDNA inheritance. We used PCR to test for the presence of all known reproductive parasites and detected a widespread infection (91.33% infection rate) of T. major with a novel Arsenophonus bacterium, as well as the infection of 2 individuals (1.16% infection rate) with a novel strain of Rickettsia. We discuss the implications for T. major phylogeography and the necessity of a bigenomic approach in arthropod population genetics.     

Genetic variation and phylogeography of the swordtail fish Xiphophorus cortezi (Cyprinodontiformes, Poeciliidae)

Swordtail fish have been studied extensively in relation to diverse aspects of biology; however, little attention has been paid to the patterns of genetic variation within and among populations of swordtails. In this study, we sequenced the mtDNA control region from 65 individuals and 10 populations of Xiphophorus cortezi to investigate the genetic variation within and among populations, including tests for correlations between genetic and geographic distances and tests for species monophyly. We found low gene and nucleotide diversity within populations and high degrees of genetic differentiation among populations. Significant and positive correlations between genetic distance and both river and straight-line geographic distance indicate that genetic differentiation among X. cortezi populations can be explained, to some extent, by an isolation-by-distance model and provide evidence of stream capture. Phylogenetic analyses suggest that X. cortezi is paraphyletic relative to X. malinche, raising questions concerning the status of these taxa as separate species.     

Molecular diversity and phylogeography of the Asian leopard cat, Felis bengalensis, inferred from mitochondrial and Y-chromosomal DNA sequences

To investigate genetic diversity and phylogeography of the Asian leopard cat (Felis bengalensis), mitochondrial DNA (mtDNA) sequences were determined for 39 individuals from various areas. Sequences combining the complete cytochrome b gene (1,140 bp) with the partial control region (646-810 bp) were classified into 24 haplotypes: 21 types from 21 animals, one from eight animals from Tsushima Islands, one from eight animals from Iriomote Island, and one from two animals from Southeast Asia. Phylogenetic trees of the 24 haplotypes clearly showed three clades: a Northern Lineage and Southern Lineages 1 and 2. The Northern Lineage consisted of animals from Tsushima Islands, the Korean Peninsula, the continental Far East, Taiwan, and Iriomote Island. Within the Northern Lineage, genetic contacts could have occurred between geographically neighboring populations before isolation by straits. Southern Lineage 1, comprising Southeast Asian animals, showed higher genetic diversity. Southern Lineage 2 had large genetic distances from other lineages. Within the control region, the Asian leopard cats shared two to four repetitive motifs, and the number of motifs and their constitution were highly variable among individuals. The motifs were polymorphic even within individuals and could be classified into 31 types. Finally, males of mtDNA Southern Lineage 1 had either of two types of the Y-chromosomal gene ZFY, whereas all males of Northern Lineage shared only one type. Our results indicate that the diversity of southern populations is higher and that genetic differentiation among northern local populations reflects past geographical isolation.     

Genetic variation and correlations between genotype and locomotor physiology in outbred laboratory house mice (Mus domesticus).

Laboratory strains of house mice (Mus domesticus) are increasingly used as model organisms in evolutionary physiology, so information on levels of genetic variation is important. For example, are levels of genetic variation comparable to those found in populations of wild house mice? We studied allozymes to estimate genetic variation in outbred Hsd:ICR mice, which have been used in several studies with evolutionary emphasis. The physiological significance of allozyme variation remains obscure. Several workers have reported relationships between multi-locus heterozygosity and metabolic traits, but endotherms have not been studied. Therefore, we also measured mice for basal metabolic rate (BMR), maximal oxygen consumption during forced treadmill exercise (VO2max), and 12 other traits related to locomotor physiology, before genotyping them for 10 allozyme loci. Four of these loci were polymorphic, all were in Hardy-Weinberg equilibrium, and inbreeding coefficients were not significantly different from zero. Average heterozygosities were 11%, similar to values reported for wild populations of house mice. Fourteen percent of the associations between single-locus genotype and physiological traits were statistically significant. Multi-locus heterozygosity was not significantly related to VO2max, but was positively correlated with BMR, a result opposite to the negative correlation between standard metabolic rate and heterozygosity reported in many ectotherms. Therefore, the proposed mechanisms for the effect of multi-locus heterozygosity on metabolic rate in ectotherms may not apply to endotherms.     

Genetic variation at 9 autosomal microsatellite loci in Asian and Pacific populations.

Genetic variation at 9 autosomal microsatellite loci (CFS1R, TH01, PLA2A, F13A1, CYP19, LPL, D20S481, D20S473, and D20S604) has been characterized in 16 Asian and Oceanic populations, mostly from mainland and insular Southeast Asia. The neighbor-joining tree and the principal coordinates analysis of the genetic relationships of these populations show a clear separation of Papua New Guinea Highlanders and, to a lesser extent, Malayan aborigines (Orang Asli or Semai) from the rest of the populations. Although the number of markers used in this study appears to be inadequate for clarifying the patterns of genetic relationships among the studied populations, in the principal coordinates analysis a geographic trend is observed in the mainland and insular Southeast Asian populations. Furthermore, in an attempt to contrast the extent of variation between autosomal and Y-chromosome-specific microsatellite loci and to reveal potential differences in the patterns of male and female migrations, we have also compared genetic variation at these 9 autosomal loci with variation observed at 5 Y-chromosome-specific microsatellites in a common set of 14 Asian populations.     

High levels of genetic variation in Indian field and house mice

Genetic variation in the Indian pygmy field miceMus booduga and theMus terricolor complex and in the house mouseMus musculus tytleri was analysed electro phoretically at 20 enzymatic and nonenzymatic protein loci. The results show an unusually high genetic variation in the field mice in terms of per cent polymorphism (P = 75 to 90 at 0-95 level), observed heterozygosity (Ho = 0.215[ ± 0.213] to 0.314 [±0.236]) and average number of alleles(A = 2.0[± 0.858] to 2.38 [±0.868]). Very high values of P,Ho andA were also observed for the house mouse. Genetic distance (D) determined by using Nei’s (1978) formula in theM. terricolor complex ranged from the lowest,D = 0.082, betweenM. terricolor I and II to the highest,D = 0.155, betweenM. terricolor II and III. Genetic distance betweenM. booduga and theM. terricolor complex was 0-259 and that between the house mouseM. m. tytleri and theM. booduga-terricolor lineage was 0.285. TheseD values corroborate that the pygmy field and house mice are closely allied.     

Genetic variation and host-parasite relations: Nematospiroides dubius in mice.

Our work deals with aspects of the genetics and immunology of host-parasite relationships as they influence the development of protective immunity and the phenomenon of coevolution. The aim is to understand parasitism through analyses of host specificity. In earlier studies we examined the inheritance of resistances in mice to infections with Nematospiroides dubius (=Heligmosomoides polygyrus) and established the predominant role played by antibodies in protective immunity. Here we report information concerning the selection of lines of N. dubius that differ in their ability to survive antagonistic immunological reactions from mice. Challenge infections with groups of these mice, immunized and protected by previous repeated infections, show that worms selected to survive the immunity that kills other worms do so by inhibiting the effectiveness of the cellular rather than humoral elements of protective immunity.     

Genetic variation in the house sparrow, Passer domesticus, in the East Midlands of England

A series of 15 samples of house sparrows taken in the East Midlands of England were screened for 14 variable and 9 invariable enzyme loci. The gene frequency data were analysed both for heterozygosity and genetic identity using Nei's and Roger's statistics. There is a cline in heterozygosity northwards across the region, and populations are closely similar. The differentiation observed is very close to that expected for a continuously distributed species with a neighbourhood area of 8.9 km² and effective population size of 999.6.     

Genetic diversity of Asian water buffalo (Bubalus bubalis): mitochondrial DNA D-loop and cytochrome b sequence variation

Swamp and river buffalo mitochondrial DNA (mtDNA) was sequenced for 303 bp of the cytochrome b gene for 54 animals from 14 populations, and for 158 bp of the D-loop region for 80 animals from 11 populations. Only one cytochrome b haplotype was found in river buffalo. Of the four haplotypes identified in swamp buffalo, one found in all populations is apparently ancestral both to the other swamp haplotypes and to the river haplotype. The phylogenetic relationships among the 33 D-loop haplotypes, with a cluster of 11 found in swamp buffalo only, also support the evolution of domesticated swamp and river buffalo from an ancestral swamp-like animal, most likely represented today by the wild Asian buffalo ( Bubalus arnee ). The time of divergence of the swamp and river types, estimated from the D-loop data, is 28 000 to 87 000 years ago. We hypothesise that the species originated in mainland south-east Asia, and that it spread north to China and west to the Indian subcontinent, where the rive type evolved and was domesticated. Following domestication in China, the domesticated swamp buffalo spread through two separate routes, through Taiwan and the Philippines to the eastern islands of Borneo and Sulawesi, and south through mainland southeast Asia and then to the western islands of Indonesia.     

Genetic and biochemical characterization of a new chymotrypsin isozyme of the house mouse,CTRA-1

Genetic variation of a codominantly inherited pancreas protease, designated CTRA-1, was discovered in the house mouse by isoelectric focusing in polyacrylamide gels. Phenotype CTRA-1A was found in MOLH/Fre and in the majority of common laboratory mouse strains. Phenotype CTRA-1B was found in PWD/Ph. It was characterized by the absence of a corresponding protease band. A third phenotype, CTRA-1C, was observed in IS/Cam and a fourth phenotype, CTRA-1D, was detected in SEG/1. CTRA-1 was found only in the pancreas and may represent the A form of chymotrypsin. The enzyme was shown to be controlled by the presumed structural locus Ctra-1 located on chromosome 8. From two backcross series, including a total of 274 animals, the gene order (Es-1, Es-9)-3.9 +/- 1.7%-Got-2-3.9 +/- 1.7%-(Es-2, Es-7, Es-23)-0.7 +/- 0.5%- Ctra-1-6.3 +/- 2.2%-Prt-2 was established.     

Genetic variation versus recombination rate in a structured population of mice

The correlation between genetic variation and recombination rate was investigated in a structured mouse population. Nucleotide sequence data from 19 autosomal DNA loci from eight inbred strains of mouse (Mus musculus) sampled from three major subspecies were analyzed. The recombination rate was estimated from the comparison of genetic and physical map distances between markers flanking a 10-cM region of each locus. The strains were categorized into four groups (subpopulations) based on geography. By partitioning the genetic diversity into within-group and among-group variation, we detected a positive correlation between the recombination rate and nucleotide diversity within groups. The level of nucleotide differentiation among groups (G(ST)) showed a negative correlation with the rate of recombination. There was no significant correlation between recombination rate and nucleotide diversity when data from different subpopulations were pooled. No correlation was detected between recombination rate and nucleotide divergence of M. musculus and M. spicilegus. These patterns deviate from the strict neutral expectation under the constant nucleotide substitution rate, and they are likely to have been formed either by a hitchhiking effect of positively selected mutants or by background selection of deleterious mutants occurring in a subdivided population. Our series of comparisons show that because a real population always has some structure, incorporation of its information is important in detecting non-neutral evolution.     

Genetic variation among Corsican and continental populations of the Eurasian treecreeper (Aves: Certhia familiaris) reveals the existence of a palaeoendemic mitochondrial lineage

In this study we investigated the phylogenetics of the Eurasian treecreeper (Certhia familiaris), a forest passerine with a wide Palaearctic range including Corsica, using three mitochondrial genes and three nuclear introns, and its phylogeographic history using the COI gene. Our phylogenetic results, including eight of the ten sub‐species currently recognized, support the monophyly of C. familiaris with respect to its Indo‐Asian sister species C. hodgsoni. C. familiaris comprises two lineages that diverged during the mid‐Pleistocene (c. 1 Myr): one palaeoendemic lineage has an allopatric range nowadays restricted to the Corsica island and the Caucasus region whereas the second one, more recent and widespread, is distributed over most of Eurasia and in northern China. The most likely scenario that may explain such a pattern is a double colonization of the western Palaearctic from the eastern range of the species. During the middle Pleistocene period, a first lineage expanded its range up into Europe but did not persist through glacial cycles except in Corsica and the Caucasus region. Later, during the upper Pleistocene, a second lineage began to diversify around 0.09 Myr, spreading towards the western Palaearctic from a unique refuge likely located in the eastern Palaearctic [correction added on 6 March 2015 after first online publication: 0.9 Myr amended to 0.09 Myr]. Apart from C. f. corsa, our results do not suggest any distinct evolutionary history for other sub‐species previously described on morphological grounds in Europe. Our study highlights the important conservation value of the Corsican treecreeper and emphasizes the major role of mature pine forests in the evolution of endemic bird taxa in Corsica. © 2015 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, 115 , 134–153.     

Lung volume, chest size, and hematological variation in low-, medium-, and high-altitude central Asian populations

To evaluate adaptive responses to high-altitude environment, we examined three groups of healthy adult males from Central Asia: 94 high-altitude (HA) Kirghiz subjects (3,200 m above sea level); 114 middle-altitude (MA) Kazakh subjects (2,100 m), and 90 low-altitude (LA) Kirghiz subjects (900 m). Data on chest size (chest perimeter and chest diameter), lung volume (forced expiratory volume (FEV) and forced expiratory volume in 1 sec (FEV1)), and hematological parameters (hemoglobin, erythrocytes, hematocrit, and SaO(2)) are discussed. The results show that 1) chest shape is less flat in the samples living at higher altitude. In the HA sample, chest perimeter is lower but chest excursion is high. 2) In the highlanders, forced vital capacity (FVC) and FEV1 are no higher than in the other samples, even when corrected for stature and body weight. The negative correlation between FVC-FEV1 and age decreases with increasing altitude. 3) The HA and MA samples have higher values of hemoglobin, erythrocytes, and hematocrit. The HA sample has lower SaO(2) and higher arterial oxygen content than the LA sample. No association between hematocrit and age was detected in the four samples. The results indicate that the high-altitude Kirghiz present features of developmental acclimatization to hypobaric hypoxia which are also strongly influenced by other major high-altitude environmental stresses.