A binary pulsar in a 53-minute orbit.

Spider pulsars are neutron stars that have a companion star in a close orbit. The companion star sheds material to the neutron star, spinning it up to millisecond rotation periods, while the orbit shortens to hours. The companion is eventually ablated and destroyed by the pulsar wind and radiation1,2. Spider pulsars are key for studying the evolutionary link between accreting X-ray pulsars and isolated millisecond pulsars, pulsar irradiation effects and the birth of massive neutron stars3-6. Black widow pulsars in extremely compact orbits (as short as 62 minutes7) have companions with masses much smaller than 0.1 M⊙. They may have evolved from redback pulsars with companion masses of about 0.1-0.4 M⊙ and orbital periods of less than 1 day8. If this is true, then there should be a population of millisecond pulsars with moderate-mass companions and very short orbital periods9, but, hitherto, no such system was known. Here we report radio observations of the binary millisecond pulsar PSR J1953+1844 (M71E) that show it to have an orbital period of 53.3 minutes and a companion with a mass of around 0.07 M⊙. It is a faint X-ray source and located 2.5 arcminutes from the centre of the globular cluster M71.

A fast radio burst source at a complex magnetized site in a barred galaxy.

Fast radio bursts (FRBs) are highly dispersed, millisecond-duration radio bursts1-3. Recent observations of a Galactic FRB4-8 suggest that at least some FRBs originate from magnetars, but the origin of cosmological FRBs is still not settled. Here we report the detection of 1,863 bursts in 82 h over 54 days from the repeating source FRB 20201124A (ref. 9). These observations show irregular short-time variation of the Faraday rotation measure (RM), which scrutinizes the density-weighted line-of-sight magnetic field strength, of individual bursts during the first 36 days, followed by a constant RM. We detected circular polarization in more than half of the burst sample, including one burst reaching a high fractional circular polarization of 75%. Oscillations in fractional linear and circular polarizations, as well as polarization angle as a function of wavelength, were detected. All of these features provide evidence for a complicated, dynamically evolving, magnetized immediate environment within about an astronomical unit (AU; Earth-Sun distance) of the source. Our optical observations of its Milky-Way-sized, metal-rich host galaxy10-12 show a barred spiral, with the FRB source residing in a low-stellar-density interarm region at an intermediate galactocentric distance. This environment is inconsistent with a young magnetar engine formed during an extreme explosion of a massive star that resulted in a long gamma-ray burst or superluminous supernova.

Diverse polarization angle swings from a repeating fast radio burst source.

Fast radio bursts (FRBs) are millisecond-duration radio transients1,2 of unknown origin. Two possible mechanisms that could generate extremely coherent emission from FRBs invoke neutron star magnetospheres3-5 or relativistic shocks far from the central energy source6-8. Detailed polarization observations may help us to understand the emission mechanism. However, the available FRB polarization data have been perplexing, because they show a host of polarimetric properties, including either a constant polarization angle during each burst for some repeaters9,10 or variable polarization angles in some other apparently one-off events11,12. Here we report observations of 15 bursts from FRB 180301 and find various polarization angle swings in seven of them. The diversity of the polarization angle features of these bursts is consistent with a magnetospheric origin of the radio emission, and disfavours the radiation models invoking relativistic shocks.

No pulsed radio emission during a bursting phase of a Galactic magnetar.

Fast radio bursts (FRBs) are millisecond-duration radio transients of unknown physical origin observed at extragalactic distances1-3. It has long been speculated that magnetars are the engine powering repeating bursts from FRB sources4-13, but no convincing evidence has been collected so far14. Recently, the Galactic magnetar SRG 1935+2154 entered an active phase by emitting intense soft γ-ray bursts15. One FRB-like event with two peaks (FRB 200428) and a luminosity slightly lower than the faintest extragalactic FRBs was detected from the source, in association with a soft γ-ray/hard-X-ray flare18-21. Here we report an eight-hour targeted radio observational campaign comprising four sessions and assisted by multi-wavelength (optical and hard-X-ray) data. During the third session, 29 soft-γ-ray repeater (SGR) bursts were detected in γ-ray energies. Throughout the observing period, we detected no single dispersed pulsed emission coincident with the arrivals of SGR bursts, but unfortunately we were not observing when the FRB was detected. The non-detection places a fluence upper limit that is eight orders of magnitude lower than the fluence of FRB 200428. Our results suggest that FRB-SGR burst associations are rare. FRBs may be highly relativistic and geometrically beamed, or FRB-like events associated with SGR bursts may have narrow spectra and characteristic frequencies outside the observed band. It is also possible that the physical conditions required to achieve coherent radiation in SGR bursts are difficult to satisfy, and that only under extreme conditions could an FRB be associated with an SGR burst.

[New insights into the role of macrophages in tumor immunotherapy].

Macrophages are the main components of the innate immunity system, derived mainly from blood monocytes, and help the host to defend itself against many pathogens and cancers. Most established tumors can educate macrophages into tumor-associated macrophages (TAMs), which contribute to tumor growth, invasion and metastasis, as well as resistance to chemotherapeutic agents and immune checkpoint inhibitors. However, when appropriately activated, macrophages can also exert anti-tumor effects through enhanced phagocytosis and cytotoxicity against tumor cells. In addition, TAMs are associated with poor prognosis and drug resistance, including immunotherapies, suggesting that macrophages are attractive targets as part of combination therapy in cancer treatment. Herein, we review the recent findings on the role of macrophages in tumor development, metastasis and immunotherapy. We focus mainly on macrophage-centered therapy, including strategies to reduce and reshape TAMs, to represent potential targets for tumor immunotherapy.

Genetic diversity and population genetic structure in native Ethiopian donkeys (Equus asinus) inferred from equine microsatellite markers.

We investigated the genetic diversity and population genetic structure of six morphologically distinct Ethiopian donkey populations using 12 equine microsatellite markers. The donkey populations were Abyssinian (AB), Afar (AF), Hararghe (HA), Ogaden (OG), Omo (OM) and Sinnar (SI). Blood samples were collected from 180 genetically unrelated donkeys (30 individuals per population). Population genetic diversity estimates showed that total number and mean number of observed alleles, average observed and expected heterozygosity were 94, 5.208 ± 0.0229, 0.555 ± 0.023 and 0.588 ± 0.022, respectively. Highly significant deficiency in heterozygote was detected within the overall samples (FIS = 0.055 ± 0.021; P < 0.001). Though highly significant (P < 0.001), heterozygote deficiency within populations relative to total population was moderate (FST = 0.046 ± 0.016), suggesting a higher diversity within the populations (95.4%) than between populations. Various genetic distance estimation methods produced a similar topology of un-rooted dendrograms that grouped the overall Ethiopian donkeys into lowland (Ogaden, Omo and Sinnar) and highland (Abyssinian, Afar and Hararghe) genetic lineages. Likewise, Bayesian clustering analysis produced a similar pattern of clustering that was highly concordant with traditional donkey classification systems in Ethiopia.

[Comparison of multi-tract PCNL and single-tract ECIRS in semisupine-lithotomy position for staghorn renal calculi].

Objective: To compare the outcomes of multi-tract percutaneous nephrolithotomy (PCNL) and simultaneous combined single-tract percutaneous nephrolithotomy and flexible ureteroscopic lithotripsy (ECIRS) as treatment for staghorn stones. Methods: The clinical data of patients with staghorn stones who were treated with multi-tract PCNL or single-tract ECIRS in Sun Yat-sen Memorial Hospital of Sun Yat-sen University from January 2015 to December 2019 were retrospectively analyzed. Two group of patients were placed in semisupine-lithotomy position (Galdakao-modified supine Valdivia position). We punctured into the renal calyces guided by ultrasonography. A F6 double J stent and a nephrostomy tube were routinely inserted in both groups. Kidney-ureter-bladder radiography (KUB) or computed tomography (CT) were done within 24 hours and 1 month after procedure to determine stone free rate (SFR). Stone free was defined as no residual stones or residual stones of <4 mm in diameter. The SFR, operating time, intraoperative and postoperative complications, and hospitalization time of the two groups were compared and analyzed. Results: A total of 135 patients were included in the study, 70 patients were female, 65 patients were male. The average age were 50.8 years. A total of 74 patients were managed by multi-tract PCNL, while 61 patients were treated by single-tract ECIRS. The mean stone diameter was (58.5±11.4) mm in the PCNL group and (57.7±11.6) mm in the ECIRS group (P=0.658). Neither the 24-hour SFR (81.1% vs 80.3%) nor one-month SFR (91.9% vs 90.2%) after procedure was significantly different between the groups (both P>0.05). The operating time was significantly longer in PCNL group compared with ECIRS group [130(100,171) vs 105(90,135) min, P=0.015]. The rate of Clavien-Dindo grade 2 or higher were significantly higher in the PCNL group than the ECIRS group (18.92% vs 1.64%, P<0.01). The PCNL group required longer hospitalization time than the ECIRS group [8 (7, 9) vs 6 (5, 8) d, P<0.01]. Conclusions: Both multi-tract PCNL and single-tract ECIRS treating staghorn stones in semisupine-lithotomy position are safe and effective. The two procedures have comparable SFR. However, the ECIRS group has lower rates of postoperative complications, shorter operating time and hospitalization time.

Identification and diversity of Y-chromosome haplotypes in Qinghai yak populations.

The aim of the present study was to perform a preliminary analysis of the characterization and diversity of Y-chromosome haplotypes/haplogroups in yak of Qinghai Province, China. A total of 322 male yaks from nine populations belonging to three officially recognized breeds (Gaoyuan, Huanhu and Datong) were sampled. Animals were genotyped using six previously reported Y-SNPs present in the SRY, USP9Y, UTY, AMELY and OFD1Y genes and four new Y-SNPs in the OFD1Y gene (g.569A>C, g.578A>C, g.608G>T and g.653G>C) identified in this study. Seven Y-chromosome haplotypes (H1-H7) were identified according to the combination of the 10 Y-SNPs. H1, H2 and H6 were the most common and shared haplotypes across all yak populations/breeds. Private haplotypes H3 and H7 were detected in the Datong breed; H4 in Guoleimude, Qumalai, Qilian, Tianjun and Ganglong populations; and H5 in Qumalai of Gaoyuan breed. Haplotype clustering and network analyses inferred two haplogroups, Y1 and Y2, indicating two divergent lineages of paternal origins of Qinghai yak. The analysis of molecular variance showed a significant difference among individuals (P < 0.0001) with more than 93% of the total genetic variation present within populations, suggesting a weak genetic structure among Qinghai yak populations. The overall Y-haplotype diversity was 0.538 ± 0.028, showing a relatively high diversity in Qinghai yak. The Gaoyuan and Datong breeds had similar haplotype diversities (0.547 ± 0.030 and 0.553 ± 0.083, respectively), which were higher than that of the Huanhu breed (0.441 ± 0.098). Our results support the conservation and sustainable use of unique yak genetic resources in Qinghai.

Detecting selection signatures on the X chromosome of the Chinese Debao pony.

The X chromosome shows a special interaction between demographic factors and genetic variation, and the analysis of X-linked genomic variation can therefore provide insights into the unique effects of demography and selection on the horse genome that cannot be readily detected by autosomal markers. Debao (DB) ponies have experienced intense selective pressure for the development of their small stature (<106 cm at adult height). To identify selective sweeps on the X chromosome of the DB pony, we performed a genome-wide scan of three Chinese horse breeds using an Equine SNP70 BeadChip. Using Yili and Mongolian horses (>134 cm at adult height) as reference groups, both FST and XP-EHH revealed that five regions on the X chromosome were under strong selection, resulting in 95 overlapping genes. Seven of these genes, SMS, PHEX, ACSL4, CHRDL1, CACNA1F, DKC1 and CDKL5, are involved in bone development, growth hormone secretion and fat deposition. The region showing the strongest selection pressure was located at the position of 86.6-87.5 Mb. The subsequent genome-wide association analysis of the adult height of three Chinese horse breeds detected the two most significant SNPs in the same region, and these two SNPs overlapped with the gene CHRDL1. As a member of the bone morphogenetic protein (BMP) superfamily, CHRDL1 antagonizes the function of BMP4 and plays an important role in embryonic bone formation and cartilage generation. Our results provide new insights into the X-linked selection in Chinese Debao pony.

Serum total bilirubin levels and disease severity in patients with stable coronary artery disease.

AIM: Serum total bilirubin (STB), a protective cardiovascular factor, was retrospectively investigated to determine the relationship between STB levels and the severity of disease in Chinese patients with stable coronary artery disease (CAD). PATIENTS AND METHODS: A total of 347 eligible patients presenting to our department from December 2007 to December 2012 were divided into tertiles according to their Syntax scores (low, moderate, and high). To clarify the association between STB levels and major adverse cardiovascular events (MACE), all patients were divided into two groups according to the median baseline STB (greater than or less than 13.2 µmol/l), which was measured after at least 12-h fast. All participants were followed for a mean of 37.1 months for MACE, including all-cause death, recurrent nonfatal myocardial infarction, and recurrent percutaneous coronary intervention. RESULTS: The STB levels were significantly lower in the high Syntax score group than those of the other groups and were negatively correlated with the Syntax score and number of diseased vessels. Follow-up data showed a higher incidence of MACE in the low STB group compared with the high STB group. Elevated STB levels predict the long-term prognosis of patients with stable angina pectoris. Finally, Kaplan-Meier analysis showed a significantly higher event-free survival rate in the patients with high STB levels than those in the low STB group. CONCLUSIONS: STB levels were independently associated with the severity of disease in patients with stable CAD. Elevated STB is associated with cardiovascular events and may be useful as a biomarker of the severity and prognosis of stable CAD.

Highly Conserved Keratin-Associated Protein 7-1 Gene in Yak, Taurine and Zebu Cattle.

Keratin-associated proteins (KRTAPs) play a critical role in cross-linking the keratin intermediate filaments to build a hair shaft. The genetic polymorphisms of the bovine KRTAP7-1 gene were investigated for the first time in this study. The complete coding sequence of the KRTAP7-1 gene in 108 domestic yak, taurine and zebu cattle from China and Indonesia were successfully amplified using polymerase chain reaction and then directly sequenced. Only two single-nucleotide polymorphisms (one nonsynonymous at c.7C/G and another synonymous at c.21C/T) and three haplotypes (BOVIN-KRTAP7-1*A, B and C) were identified in the complete coding sequence of the bovine KRTAP7-1 gene among all animals. There was no polymorphism across three Chinese indigenous yak breeds and one Indonesian zebu cattle population, all sharing the BOVINKRTAP71*A haplotype. The four taurine cattle populations also had BOVIN-KRTAP7-1*A as the most common haplotype with a frequency of 0.80. The frequency of novel haplotype BOVIN-KRTAP7-1*B was only 0.07 present in one heterozygous animal in each of the four taurine cattle populations, while BOVINKRTAP7- 1*C was only found in a Simmental and a local Chinese Yellow cattle population with frequencies of 0.17 and 0.36, respectively. The monomorphic yak KRTAP7-1 gene in particular, and highly conserved bovine, sheep and goat KRTAP7-1 genes in general, demonstrated its unique intrinsic structural property (e.g., > 21% high glycine content) and primary functional importance in supporting the mechanical strength and shape of hair.

[Feasibility and value of index of microcirculatory resistance in patients with acute myocardial infarction after primary percutaneous coronary intervention].

Objective: To evaluate the feasibility of detecting index of microcirculatory resistance (IMR) and the relationship between IMR and left ventricular (LV) systolic function after acute myocardial infarction (AMI) undergoing primary percutaneous coronary intervention (PCI). Methods: The patients with first AMI received primary PCI in Peking University Third Hospital were enrolled from January 2014 to March 2016. IMR were measured immediately after PCI by using pressure/temperature wire. The relationship between IMR and left ventricular ejection fraction (LVEF) assessed by echocardiography at first day and 6 months after admission was evaluated. Results: Twenty-eight patients with anterior wall AMI were enrolled, with an average age (56±13) years. The success rate of IMR detection was 100%. The mean IMR was (33±18 )mmHg·s. There was no complication related to intravenous adenosine triphosphate (ATP) (140 µg· kg(-1)· min(-1)). The IMR was negatively correlated with TIMI blood flow grade after primary PCI (r=-0.386, P=0.043), and positively correlated with female gender, CK peak value and TnT peak value (r=0.430, P=0.022; r=0.431, P=0.025; r=0.434, P=0.024). After 6 months of follow-up, no adverse cardiovascular events (including cardiac death, nonfatal myocardial infarction, malignant arrhythmia, unplanned revascularization, hospitalization for unstable angina pectoris and severe heart failure requiring hospitalization) occurred. LVEF increased significantly compared with the first day after PCI (0.54±0.08 vs 0.47±0.06, P=0.001), and IMR was negatively correlated with LVEF after 6 months (r=-0.477, P=0.014). Multivariable linear regression analysis showed that CK peak and IMR were predictors of LVEF after six months ( ß=-0.595, t=-3.814, P=0.01; ß=-0.352, t=-2.26, P=0.036). Conclusions: Immediate detection of IMR in patients with anterior wall AMI after PCI is safe and feasible. The immediate IMR after PCI reflects the extent of myocardial necrosis and myocardial perfusion, and is a predictor of LVEF at 6 months after PCI.

[Related factors for the development of fulminant myocarditis in adults].

Objective: To determine the early recognizable factors related to patients with fulminant myocarditis. Methods: Medical records from 60 adult patients who were diagnosed with acute viral myocarditis from January 2003 to September 2016 in our hospital were retrospectively reviewed, and divided into the fulminant group (n=9) and the non-fulminant group (n=51). Clinical presentations, biochemical markers, electrocardiography and echocardiography features on admission were analyzed. Results: Prevalence of syncope (33.3%(3/9) vs. 2.0% (1/51), P=0.009) and fatigue (77.8% (7/9) vs. 21.6% (11/51) , P=0.002) was significantly higher, while the duration from flu-like syndromes to chest discomfort was shorter ((2.0±1.8) days vs. (4.5±3.5) days, P=0.041) in the fulminant group than that in the non-fulminant group. Systolic blood pressare (SBP) ((94±14) mmHg(1 mmHg=0.133 kPa) vs. (117±12)mmHg, P=0.001) and left ventricular ejection fraction((49±12)% vs. (60±13)%, P=0.016) were significantly lower, while heart rate ((99±20)bpm vs. (84±19)bpm, P=0.040) and NT-proBNP concentration ((7 962 (1 470, 23 849) ng/L vs. 1 771 (45, 2 380) ng/L, P=0.000) were significantly higher in the fulminant group than those in the non-fulminant group. PR interval was longer (199 (140, 416) ms vs. 156 (112, 204) ms, P=0.021), QRS complex was wider ((127±14)ms vs. (95±13)ms, t=-6.647, P<0.001) in the fulminant group than those in the non-fulminant group. Prolonged QRS duration≥120 ms was more often in fulminant group (77.8%(7/9) vs. 5.9%(3/51), P=0.000). Multivariate analysis revealed that PR interval (adjusted odd ratio 1.044, 95%CI 1.005-1.084, P=0.025) and QRS complex width (adjusted odd ratio 1.252, 95%CI 1.045-1.501, P=0.015) were the independent risk factors significantly associated with fulminant myocarditis. Conclusions: The risk of a fulminant course of acute myocarditis is higher in patients with elevated NT-proBNP, reduced left ventricular ejection fraction, and conduction disturbances at admission. Prolonged PR interval and widened QRS complex on admission are independent risk factors for developing fulminant myocarditis in adult patients with acute viral myocarditis.

Metallophthalocyanines as triplet sensitizers for highly efficient photon upconversion based on sensitized triplet-triplet annihilation.

Soluble palladium and platinum phthalocyanines with coumarin moieties were synthesized with Q bands in the red and near-IR regions, in which the molar extinction coefficients were up to 1.01 × 10(5) cm(-1) mol(-1). These metallophthalocyanines were coupled with rubrene and applied in photon upconversion systems based on triplet-triplet annihilation. The highest upconversion efficiency of the palladium phthalocyanine was 5.6%, which is higher than that of the platinum phthalocyanine-rubrene system. The larger molar extinction coefficient resulted in high upconversion capability (>10(5) cm(-1) mol(-1)) and low saturation incident power (<20 mW cm(-2)).

Multilocus genotypic data reveal high genetic diversity and low population genetic structure of Iranian indigenous sheep.

Iranian livestock diversity is still largely unexplored, in spite of the interest in the populations historically reared in this country located near the Fertile Crescent, a major livestock domestication centre. In this investigation, the genetic diversity and differentiation of 10 Iranian indigenous fat-tailed sheep breeds were investigated using 18 microsatellite markers. Iranian breeds were found to host a high level of diversity. This conclusion is substantiated by the large number of alleles observed across loci (average 13.83, range 7-22) and by the high within-breed expected heterozygosity (average 0.75, range 0.72-0.76). Iranian sheep have a low level of genetic differentiation, as indicated by the analysis of molecular variance, which allocated a very small proportion (1.67%) of total variation to the between-population component, and by the small fixation index (FST  = 0.02). Both Bayesian clustering and principal coordinates analysis revealed the absence of a detectable genetic structure. Also, no isolation by distance was observed through comparison of genetic and geographical distances. In spite of high within-breed variation, signatures of inbreeding were detected by the FIS indices, which were positive in all and statistically significant in three breeds. Possible factors explaining the patterns observed, such as considerable gene flow and inbreeding probably due to anthropogenic activities in the light of population management and conservation programmes, are discussed.

[The expression of serum endoplasmic reticulum stress protein-78 in obstructive sleep apnea patients].

OBJECTIVE: This study aimed to detect serum level of glucose regulated protein 78(GRP78) in patients with obstructive sleep apnea(OSA) and explore the relationship between endoplasmic reticulum stress and the pathophysiology of OSA. METHODS: A total of 91 patients with OSA were enrolled in this study, including 30 mild, 28 moderate and 33 severe. The other 27 obese subjects were of age, gender and BMI matched group. Eleven moderate or severe OSA patients were administrated with continuous positive airway pressure (CPAP) treatment for 24 hours. Polysomnography, apnea hypopnea index (AHI), lowest arterial oxygen saturation(SaO2) and percentage of time spent at SaO2 below 90% (SIT90) were measured before and after sleep. Serum GRP78 was measured by ELISA. RESULTS: The expression of GRP78 in mild(3.42±0.97)µg/L, moderate(2.67±1.14)µg/L and severe(2.62±1.11)µg/L OSA groups was significantly higher than in control group(1.75±0.41)µg/L (P<0.05). The GRP78 level in mild OSA group was significantly higher than either moderate or severe OSA group (P<0.05). After 24 h treatment of CPAP, serum GRP78 level decreased significantly [(1.77±0.39)µg/L vs(2.84±0.39)µg/L; P<0.05]. CONCLUSIONS: Endoplasmic reticulum stress involves in the pathophysiology of patients with OSA. Higher GRP78 level in mild OSA patients suggests that endoplasmic reticulum related protein GRP 78 might rise then fall during exacerbation of OSA.

[The analysis of pattern visual evoked potential in obstructive sleep apnea syndrome].

OBJECTIVE: To objectively evaluate visual function by pattern visual evoked potential (PVEP) and its related factors in patients with obstructive sleep apnea syndrome (OSAS)without any ocular symptoms. METHODS: Eighty-three newly diagnosed OSAS and 18 normal subjects were enrolled in the study. The OSAS patients were divided into mild (n=11), moderate(n=17) and severe (n=55) groups based on the apnea-hypopnea index(AHI). Before the polysomnography(PSG) test, all participants underwent a PVEP examination measuring the latency and amplitude of P100. RESULTS: Compared to healthy controls, the latency of P100 was significantly increased in OSAS patients [controls group: 97(95-100) ms, mild OSAS group: 101(98-103) ms, moderate OSAS group: 101(98-105) ms, severe OSAS group: 105(101-108) ms, all P<0.05], and the amplitude of P100 was significantly reduced [controls group: 9(8-10) µV, mild OSAS group: 7(5-8) µV, moderate OSAS group: 6(5-7) µV, severe OSAS group: 6(4-7) µV, all P<0.05]. The severe group showed significantly longer latency of P100 when compared with mild and moderate groups(P<0.05). In the OSAS patients, univariate analysis showed that, the latency of P100 was correlated with ODI, T90, AHI, sleep efficiency, minimum SaO2, and mean SaO2, and the amplitude of P100 was statistically associated with sleep efficiency .But the stepwise multiple linear regression analysis revealed that only AHI was significantly correlated with the latency of P100 (r=0.275, P<0.01). CONCLUSION: Abnormal PVEP was found in patients with OSAS without any clinical manifestations of the optic neuropathy. The dysfunction of optic nerve was significantly associated with AHI and sleep efficiency.

Analysis of agouti signaling protein (ASIP) gene polymorphisms and association with coat color in Tibetan sheep (Ovis aries).

Tibetan sheep, an indigenous breed, have a wide variety of phenotypes and a colorful coat, which make this breed an interesting model for evaluating the effects of coat-color gene mutations on this phenotypic trait. The agouti signaling protein (ASIP) gene is a positional candidate gene, as was inferred based on previous study. In our research, ASIP gene copy numbers in genomic DNA were detected using a novel approach, and the exon 2 g.100-104 mutation and copy number variation (CNV) of ASIP were associated with coat color in 256 sheep collected from eight populations with different coat colors by high-resolution melting curve assay. We found that the relative copy numbers of ASIP ranged from one to eight in Tibetan sheep. All of the g.100-104 genotypes in the populations were in Hardy-Weinberg equilibrium, and there was no relationship between the g.100-104 genotype and coat color (P > 0.05). The single ASIP CNV allele was found to be almost entirely associated with solid-black coat color; however, not all solid-black sheep displayed the putative single ASIP CNV genotype. From our study, we speculate that the ASIP CNV is under great selective pressure and the single ASIP CNV allows selection for black coat color in Tibetan sheep, but this does not explain all black phenotypes in Tibetan sheep.