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1.
We aimed to determine whether casein variants that are currently segregating in ovine populations existed before the domestication of sheep or, to the contrary, if their emergence is much more recent. To this end, we have retrieved whole-genome sequences from Iranian and domestic sheep from Africa, Europe, South and East Asia and West Asia. Population structure analysis based on 55,352,935 SNPs revealed a clear separation between Iranian mouflons and domestic sheep. Moreover, we also observed a strong genetic differentiation between Iranian mouflons sampled in geographic areas close to Tehran and Tabriz. Based on sequence data, hundreds of SNPs mapping to the casein αS1 (CSN1S1, 248 SNPs), casein αS2 (CSN1S2, 268 SNPs), casein ß (CSN2, 146 SNPs) and casein κ (CSN3, 112 SNPs) genes were identified. Approximately 25–63.02% of the casein variation was shared between Iranian mouflons and domestic sheep, and the four domestic sheep populations also shared 44.2–57.4% of the casein polymorphic sites. These findings suggest that an important fraction of the casein variation present in domestic sheep was already segregating in the mouflon prior to its domestication. Genomic studies performed in horses and dogs are consistent with this view, suggesting that much of the diversity that we currently detect in domestic animals comes from standing variation already segregating in their wild ancestors. 相似文献
2.
B. Nussberger M. P. Greminger C. Grossen L. F. Keller P. Wandeler 《Molecular ecology resources》2013,13(3):447-460
Introgression can be an important evolutionary force but it can also lead to species extinction and as such is a crucial issue for species conservation. However, introgression is difficult to detect, morphologically as well as genetically. Hybridization with domestic cats (Felis silvestris catus) is a major concern for the conservation of European wildcats (Felis s. silvestris). The available morphologic and genetic markers for the two Felis subspecies are not sufficient to reliably detect hybrids beyond first generation. Here we present a single nucleotide polymorphism (SNP) based approach that allows the identification of introgressed individuals. Using high‐throughput sequencing of reduced representation libraries we developed a diagnostic marker set containing 48 SNPs (Fst > 0.8) which allows the identification of wildcats, domestic cats, their hybrids and backcrosses. This allows assessing introgression rate in natural wildcat populations and is key for a better understanding of hybridization processes. 相似文献
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Fissions,fusions, and translocations shaped the karyotype and multiple sex chromosome constitution of the northeast‐Asian wood white butterfly,Leptidea amurensis
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Jindra Šíchová Mizuki Ohno Vlad Dincă Michihito Watanabe Ken Sahara František Marec 《Biological journal of the Linnean Society. Linnean Society of London》2016,118(3):457-471
Previous studies have shown a dynamic karyotype evolution and the presence of complex sex chromosome systems in three cryptic Leptidea species from the Western Palearctic. To further explore the chromosomal particularities of Leptidea butterflies, we examined the karyotype of an Eastern Palearctic species, Leptidea amurensis. We found a high number of chromosomes that differed between the sexes and slightly varied in females (i.e. 2n = 118–119 in females and 2n = 122 in males). The analysis of female meiotic chromosomes revealed multiple sex chromosomes with three W and six Z chromosomes. The curious sex chromosome constitution [i.e. W1–3/Z1–6 (females) and Z1–6/Z1–6 (males)] and the observed heterozygotes for a chromosomal fusion are together responsible for the sex‐specific and intraspecific variability in chromosome numbers. However, in contrast to the Western Palearctic Leptidea species, the single chromosomal fusion and static distribution of cytogenetic markers (18S rDNA and H3 histone genes) suggest that the karyotype of L. amurensis is stable. The data obtained for four Leptidea species suggest that the multiple sex chromosome system, although different among species, is a common feature of the genus Leptidea. Furthermore, inter‐ and intraspecific variations in chromosome numbers and the complex meiotic pairing of these multiple sex chromosomes indicate the role of chromosomal fissions, fusions, and translocations in the karyotype evolution of Leptidea butterflies. 相似文献
5.
Mapping of the mouse X chromosome using random genomic probes and an interspecific mouse cross. 总被引:11,自引:2,他引:9
Two libraries enriched in murine X chromosome material have been constructed in the lambda vector NM 1149 from flow-sorted chromosomes. Inserts of unique genomic sequence DNA were purified and their X chromosome specificity characterised by hybridisation to a panel of somatic cell hybrid lines. Of the first five such X chromosome-specific probes characterised, all detect restriction fragment length polymorphisms (RFLPs) between inbred mouse laboratory strains such as C57BL/6 and BALB/c and the SPE/Pas mouse strain established from a wild Mus spretus mouse, when their DNAs are digested with the restriction enzyme TaqI. Taking advantage of these RFLPs, all five probes have been localised on the X chromosome using an interspecific backcross between the B6CBARI and SPE/Pas mouse strains segregating the X chromosome markers hypoxanthine phosphoribosyl transferase (Hprt) and Tabby (Ta). Three of the probes map to the region between the centromere and Hprt, and two distal to Ta. Since such X-specific sequence probes detect RFLPs between M. spretus and M. musculus domesticus DNAs with high frequency, a large panel of well localised probes should soon be available for studies of biological problems associated with the X chromosome which can best be approached using the murine species. 相似文献
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Follicular atresia in the ovary of the domestic goose was investigated by light microscopic, steroid RIA and lysosomal enzyme activity measuring methods during the spring reproduction cycle. Degenerative processes are associated with the transformation and proliferation of granulosa, internal and external thecal cells in the follicle. Seven types of atretic follicles were identified on the basis of the presence, absence or dominance of cells containing lipids and synthesizing steroids. Conclusive evidence for the relation between cell type and hormone content was found only in one type: in type 6, stromal glandular cells show an extremely intensive PROG synthesizing activity. In the other types it was shown that glandular type of cells which become proliferative during atresia possess a relatively uniform steroid synthesizing ability. This uniformity is also seen in the high activity of lysosomal enzymes regardless of the size and type of atretic follicles. 相似文献
9.
Toshihito Takagi Yoshiaki Tsuda Harumi Torii Hidetoshi B. Tamate Shingo Kaneko Junco Nagata 《Population Ecology》2022,64(2):150-160
The effect of sex-biased dispersal in mammalian ecology and evolution can be elucidated by focusing on maternally or paternally inherited DNA polymorphisms. In sika deer, the genetic structure of the maternal lineage has been clarified by studies based on mitochondrial DNA variation. However, the genetic structure of the paternal lineage has not been well analyzed due to the limited number of point mutations in Y chromosome sequences. In this study, we focused on mutations of highly polymorphic simple sequence repeats (SSRs) in the Y chromosome and developed 16 Y chromosome SSR markers to evaluate male-biased dispersal in sika deer. In total, 55 alleles and 31 multi-locus haplotypes were detected from these 16 loci, revealing clear genetic differentiation among populations (F′ST = 0.783). In particular, there were unique alleles for the native individuals on Tanegashima and Yakushima Islands and introduced exotic individuals from Taiwan. These markers are highly useful for evaluating not only historical male-mediated dispersal, genetic structure, and demography of the native populations in Japan, but also the impact of artificial introductions on hybridization, especially the introgression of alleles from escaped farmed individuals to native populations. 相似文献
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A combined method for clearing soft tissues, staining cartilage and bone, and injecting the vascular system of small mammals was developed using Mus musculus (house mouse). Mammalian muscle tissue remains milky or even opaque after "clearing" by previous techniques due to the relatively high content of intramuscular fat. A method employing chloroform-ethanol successfully renders soft tissues of mammalian specimens translucent without damaging or bleeding color from the latex injected in the circulatory system. Resulting specimens yield an excellent view of the skeletal system and the injected vascular system without obstruction by opaque tissues or disruption by physical removal of connective tissue. 相似文献
12.
M. R. Warburg 《Journal of Ethology》2000,18(1):59-63
Scorpion cohabitation was studied qualitatively and quantitatively for several years in the field and in controlled experimental
conditions in the laboratory. In the field, several cases were recorded of scorpions sharing the same shelter, either intra-
or interspecifically. Intraspecific cohabitation was more prevalent than interspecific cohabitation. Among the five scorpion
species studied here, Compsobuthus werneri judaicus shows the highest degree of sociality and aggregates both intra- and interspecifically. Leiurus quinquestriatus was never observed to cohabit interspecifically. Both Buthotus judaicus and C. werneri judaicus shared shelters with other scorpions more frequently during the wet season, whereas Nebo hierichonticus and Scorpio maurus fuscus cohabitated more often during the dry season. Under controlled laboratory conditions, density and availability of either
food or shelter appear to be significant in facilitating cohabitation, even in the more aggressive species.
Received: April 28, 1999 / Accepted: July 30, 1999 相似文献
13.
M. Ruiz Garcia 《Genetica》1990,82(3):215-221
New genetic profiles of domestic cat populations were studied in different parts of the Spanish Mediterranean coast. The t
b frequency is the most outstanding differentiated factor between the populations analyzed. The low t
b frequencies found in Barcelona and other Catalan localities are the most important characteristic of these populations and, probably, find an explanation in the extraordinarily high historical and commercial relationships between Barcelona and the Eastern Mediterranean (Greece, especially) during the 14th and 15th centuries. In other Spanish Mediterranean littoral cities the t
b frequencies reach higher values and are more similar to those found in other Western European cat populations. Significant differences found in certain allelic frequencies (Orange and Blotched) caused by the urban-rural effect are discovered between Barcelona and two nearby rural cat populations. 相似文献
14.
Müller S Stanyon R O'Brien PC Ferguson-Smith MA Plesker R Wienberg J 《Chromosoma》1999,108(6):393-400
We used multidirectional chromosome painting with probes derived by bivariate fluorescence-activated flow sorting of chromosomes
from human, black lemur (Eulemur
macaco
macaco) and tree shrew (Tupaia
belangeri, order Scandentia) to better define the karyological relationship of tree shrews and primates. An assumed close relationship
between tree shrews and primates also assists in the reconstruction of the ancestral primate karyotype taking the tree shrew
as an ”outgroup” species. The results indicate that T.
belangeri has a highly derived karyotype. Tandem fusions or fissions of chromosomal segments seem to be the predominant mechanism in
the evolution of this tree shrew karyotype. The 22 human autosomal painting probes delineated 40 different segments, which
is in the range found in most mammals analyzed by chromosome painting up to now. There were no reciprocal translocations that
would distinguish the karyotype of the tree shrew from an assumed primitive primate karyotype. This karyotype would have included
the chromosomal forms 1a, 1b, 2a, 2b, 3/21, 4–11, 12a/22a, 12b/22b, 13, 14/15, 16a, 16b, 17, 18, 19a, 19b, 20 and X and Y
and had a diploid chromosome number of 2n=50. Of these forms, chromosomes 1a, 1b, 4, 8, 12a/22a, and 12b/22bmay be common derived characters that would link the tree
shrew with primates. To define the exact phylogenetic relationships of the tree shrews and the genomic rearrangements that
gave rise to the primates and eventually to humans further chromosome painting in Rodentia, Lagomorpha, Dermoptera and Chiroptera
is needed, but many of the landmarks of genomic evolution are now known.
Received: 11 February 1999; in revised form: 17 June 1999 / Accepted: 20 July 1999 相似文献
15.
《Animal reproduction science》1998,51(4):321-332
The processes of capacitation and acrosomal exocytosis of dog spermatozoa in vitro have yet to be fully investigated. Firstly, we investigated the effectiveness of a technique for staining dog spermatozoa with the fluorescent labels Hoechst 33258 and chlortetracycline. A modified fluorescence microscopy staining method was shown to be effective for the assessment of both viability and functional status in this species. Secondly, the presence of the ionophore A23187 in culture medium was shown to promote capacitation and the acrosome reaction of dog spermatozoa. We have therefore established that this dual fluorescent staining method can be used for monitoring these events in the dog, and it may be useful in future studies of optimal in vitro culture conditions. 相似文献
16.
M F Seldin L Martinez T A Howard S L Naylor A Y Sakaguchi 《Cytogenetics and cell genetics》1990,54(1-2):68-70
Melanoma growth stimulatory activity (Mgsa) is a polypeptide mitogen and a possible autocrine growth factor for melanoma and other tumor cells. A restriction fragment length variant of Mgsa was followed in interspecific backcross mic Mgsa was localized between Afp and Gus on mouse chromoson 5, distal to known loci affecting skin pigmentation. 相似文献
17.
Extreme drought and salt resistant plant Reaumuria soongorica is of great potential for revealing genetic bases unique to naturally stress-tolerant plants. A preliminary genome survey,
including chromosome number, karyotype, chromosomal localization of 45S rDNA loci and genome size was conducted with R. soongorica collected from Lanzhou, China. Chromosome counting showed that R. soongorica is diploid with chromosome number of 22. Karyotypical analysis illustrated that the chromosomes size ranges from 3.38 to
5.51 μm, and the chromosomal formula is 2n = 2x = 22 = 4 m + 14sm + 4st. Fluorescence in situ hybridization revealed that four pairs of 45SrDNA signals were detected at
the end of R. soongorica chromosomes. The flow cytometry analysis indicated that the mean C value of R. soongorica is 0.806 pg with predicted genome size of about 778 Mb. The results indicate that the extreme drought and salt resistance
of R. soongorica was not attributed to a big and complicate genome and also offer some clues in resolving the problems of taxonomy and evolution
in Tamaricaceae. 相似文献
18.
Fibroblasts from a carrier of an X/1 translocation, 46,XY,t(X;1)(q28;q31), were fused with Chinese hamster cells. The resulting hybrids were analyzed for human No. 1 and X-chromosome markers. The data indicate that the loci for PGM1, PGD, PPH, and GuK1 are situated either in the long arm proximal to a break point in band 1q31 or in the short arm. The loci for Pep-C, FH, and GuK1 are located distal to the break point. HPRT and G6PD are probably situated distal to a break point in band q28 of the X chromosome; alpha-Gal A is situated proximal to the break point, either on the long or short arm of the chromosome. 相似文献
19.
Bioaccumulation of lithium by marine organisms in European, American, and Asian coastal zones: microanalytic study using secondary ion emission 总被引:1,自引:0,他引:1
C Chassard-Bouchaud P Galle F Escaig M Miyawaki 《Comptes rendus de l'Académie des sciences. Série III, Sciences de la vie》1984,299(18):719-724
37 species of aquatic mammals, fish, crustacea, annelids, molluscs belonging to cephalopods, gasteropods and lamellibranchs were collected from coastal waters of France: North Sea, English Channel, Atlantic Ocean, Mediterranean Sea, from Greece: Aegian Sea, from North America: Atlantic Ocean and from Japan: Pacific Ocean, Sea of Japan and East China Sea. Microanalyses which were performed on organs and tissues, using secondary ion mass spectrometry, revealed high concentrations of lithium, which is commonly used in human therapy, but is also toxic in low amounts. The retention of this metal by the marine organisms appears as a general phenomenon independent of their biotope and geographical origin; the highest lithium levels were detected in the fish muscles (= edible part). 相似文献
20.
Tiffany M Knight Jonathan M Chase Charles W Goss Jennifer J Knight 《Journal of vector ecology》2004,29(2):277-284
We examined the effect of predation by the backswimmer (Notonecta undulata; Hemiptera: Notonectidae), competition by zooplankton and snails, and both predation and competition on the survival and development time of larval Anopheles quadrimaculatus mosquitoes in experimental mesocosms. We found that both predation and interspecific competition greatly reduced the survivorship of larvae and the number of larvae emerging into adulthood. Treatments with both predators and competitors had fewer larvae transitioning among instars and into adulthood but not in an additive way. In addition, mosquito larvae in the presence of predators and competitors took two days longer to emerge than where predators and competitions were absent. Our work provides evidence that biotic interactions, such as predation and competition, can strongly regulate the number of mosquito larvae by reducing the number of larvae that survive through instars and to emergence and by increasing the generation time. 相似文献