Integrating genomics and transcriptomics to identify candidate genes for high-altitude adaptation and egg production in Nixi chicken.

1. This study combined genome-wide selection signal analysis with RNA-sequencing to identify candidate genes associated with high altitude adaptation and egg production performance in Nixi chickens (NXC).2. Based on the whole-genome data from 20 NXC (♂:10; ♀:10), the population selection signal was analysed by sliding window analysis. The selected genes were screened by combination with the population differentiation statistic (FST). The sequence diversity statistic (θπ). RNA-seq was performed on the ovarian tissues of NXC (n = 6) and Lohmann laying hens (n = 6) to analyse the differentially expressed genes (DEGs) between the two groups. The functional enrichment analysis of the selected genes and differentially expressed genes was performed.3. There were 742 genes under strong positive selection and 509 differentially expressed genes screened in NXC. Integrated analysis of the genome and transcriptome revealing 26 overlapping genes. The candidate genes for adaptation to a high-altitude environment, as well as for egg production, disease resistance, vision and pigmentation in NXC were preliminarily screened.4. The results provided theoretical guidance for further research on the genetic resource protection and utilisation of NXC.

Deep learning for the early identification of periodontitis: a retrospective, multicentre study.

AIM: To develop a deep-learning model to help general dental practitioners diagnose periodontitis accurately and at an early stage. MATERIALS AND METHODS: First, the panoramic radiographs (PARs) from the Second Affiliated Hospital of Nanchang University were input into the convolutional neural network (CNN) architecture to establish the PAR-CNN model for healthy controls and periodontitis patients. Then, the PARs from the Affiliated Hospital of Jiangxi University of Traditional Chinese Medicine were included in the second testing set to validate the effectiveness of the model with data from two centres. Heat maps were produced using a gradient-weighted class activation mapping method to visualise the regions of interest of the model. The accuracy and time required to read the PARs were compared between the model, periodontal experts, and general dental practitioners. Areas under the receiver operating characteristic curve (AUCs) were used to evaluate the performance of the model. RESULTS: The AUC of the PAR-CNN model was 0.843, and the AUC of the second test set was 0.793. The heat map showed that the regions of interest predicted by the model were periodontitis bone lesions. The accuracy of the model, periodontal experts, and general dental practitioners was 0.800, 0.813, and 0.693, respectively. The time required to read each PAR by periodontal experts (6.042 ± 1.148 seconds) and general dental practitioners (13.105 ± 3.153 seconds), which was significantly longer than the time required by the model (0.027 ± 0.002 seconds). CONCLUSION: The ability of the CNN model to diagnose periodontitis approached the level of periodontal experts. Deep-learning methods can assist general dental practitioners to diagnose periodontitis quickly and accurately.

Observation of a Strongly Isospin-Mixed Doublet in

ß decay of proton-rich nuclei plays an important role in exploring isospin mixing. The ß decay of ^{26}P at the proton drip line is studied using double-sided silicon strip detectors operating in conjunction with high-purity germanium detectors. The T=2 isobaric analog state (IAS) at 13 055 keV and two new high-lying states at 13 380 and 11 912 keV in ^{26}Si are unambiguously identified through ß-delayed two-proton emission (ß2p). Angular correlations of two protons emitted from ^{26}Si excited states populated by ^{26}P ß decay are measured, which suggests that the two protons are emitted mainly sequentially. We report the first observation of a strongly isospin-mixed doublet that deexcites mainly via two-proton decay. The isospin mixing matrix element between the ^{26}Si IAS and the nearby 13 380-keV state is determined to be 130(21) keV, and this result represents the strongest mixing, highest excitation energy, and largest level spacing of a doublet ever observed in ß-decay experiments.

Poor sleep is associated with higher blood pressure and uterine artery pulsatility index in pregnancy: a prospective cohort study.

OBJECTIVE: To elucidate the association between sleep disturbances and blood pressure as well as uterine artery Doppler during pregnancy in women with no pre-existing hypertension. DESIGN: Prospective cohort study. SETTING: Outpatient specialist clinics at KK Women's and Children's Hospital, Singapore. POPULATION: Women with viable singleton pregnancies confirmed by ultrasonography at less than 14 weeks of amenorrhoea at first visit. METHODS: In all, 926 subjects were recruited for this study in the outpatient specialist clinics at KK Women's and Children's Hospital, Singapore, between 1 September 2010 and 31 August 2014. They were followed up throughout pregnancy with sleep quality, blood pressure and uterine artery Doppler assessed at each visit. MAIN OUTCOME MEASURES: Sleep quality, blood pressure and uterine artery Doppler. RESULTS: Sleep progressively worsened as pregnancy advanced. Shorter sleep duration and poorer sleep efficiency were associated with higher blood pressure, especially in the first trimester. Mixed model analysis demonstrated an overall positive association between sleep quality represented by Pittsburgh Sleep Quality Index (PSQI) score and diastolic blood pressure (DBP) (P < 0.001) and mean arterial pressure (MAP) (P = 0.005) during pregnancy after considering all trimesters. Sleep duration was found to be negatively associated with both systolic blood pressure (SBP) (P = 0.029) and DBP (P = 0.002), whereas sleep efficiency was negatively correlated with DBP (P = 0.002) only. Overall poor sleep during pregnancy was also found to be associated with a higher uterine artery pulsatility index. CONCLUSION: Our prospective study demonstrated that poor sleep quality is significantly associated with higher blood pressure and uterine artery pulsatility index during pregnancy. TWEETABLE ABSTRACT: Poor sleep quality is significantly associated with higher blood pressure and higher uterine artery pulsatility index during pregnancy.

Gene mapping reveals the association between tyrosine protein kinase Abl1 and the silk yield of Bombyx mori.

The Z chromosome of the silkworm contains a major gene that influences silk yield. This major locus on chromosome Z accounts for 35.10% of the phenotypic variance. The location and identification of the gene have been a focus of silkworm genetics research. Unfortunately, identification of this gene has been difficult. We used extreme phenotype subpopulations and selected from a backcross population, BC1 M, which was obtained using the high-yield strain 872B and the low-yield strain IS-Dazao as parents, for mapping the gene on the chromosome Z. The candidate region was narrowed down to 134 kb at the tip of the chromosome. BmAbl1 in this region correlated with silk gland development by spatiotemporal expression analysis. This gene was differentially expressed in the posterior silk glands of the high- and low-yield strains. In BmAbl1, an insertion-deletion (indel) within the 10th exonic region and an SNP within the 6th intronic region were detected and shown to be associated with cocoon shell weight in 84 Bombyx mori strains with different yields. Nucleotide diversity analysis of BmAbl1 and its 50 kb flanking regions indicated that BmAbl1 has experienced strong artificial selection during silkworm domestication. This study is the first to identify the genes controlling silk yield in the major QTL of the Z chromosome using forward genetics.

[The role of nitric oxide in the inhibitory effects of exogenous hydrogen sulfide on rat colonic smooth muscle contraction].

Objective: To investigate the role of nitric oxide (NO) in hydrogen sulfide (H(2)S)-induced inhibition upon colonic smooth muscle contraction. Methods: Immunohistochemistry was applied to observe the distribution of H(2)S-producing enzymes CBS and CSE in adult male Wistar rats. Organ bath system was used to observe the spontaneous contraction of colonic smooth muscle. Patch clamp technique was applied to record currents of L-type calcium channel (I(Ca,L)) in smooth muscle cells. Results: Specific immunoreactivity for CSE and CBS was observed in mucosa, smooth muscle and enteric plexus of rat proximal colon. NaHS elicited relaxation in a concentration-dependent manner upon muscle contraction in the presence of tetrodotoxin. The NaHS IC(50) of LM was 917.6 µmol/L (95% CI: 776.3-1 085 µmol/L, n=6) and the NaHS IC(50) of CM was 730.4 µmol/L (95% CI: 592.2-900.8 µmol/L, n=6). The SNP-induced relaxation in muscle strips was partially reversed by NaHS (P<0.05). Instead, the relaxation caused by NaHS was decreased by the sGC inhibitor ODQ but affected neither by NO precursor L-arginine, the NO inhibitor L-NNA nor the competitive cGMP antagonist PET-cGMP. NaHS (100 µmol/L) increased I(Ca,L) while NaHS (300 µmol/L) decreased the peak I(Ca,L) with modifying the ion channel characteristics (P<0.05). Conclusions: Exogenous hydrogen sulfide might have a dual effect on colonic motility and its inhibitory effect might be independent of NO signaling system. L-type calcium channel may play an important role during the process of H(2)S modulating colonic contraction.

[Suggestions for thoracic surgery clinical practice in non-epidemic area of 2019 coronavirus disease].

In this paper, the mechanism of destroying human alveolar epithelial cells and pulmonary tissue by 2019 novel coronavirus (2019-nCoV) was discussed firstly. There may be multiple mechanisms including killing directly the target cells and hyperinflammatory responses. Secondly, the clinical features, CT imaging, short-term and long-term pulmonary function damage of the 2019 coronavirus disease (COVID-19) was analyzed. Finally, some suggestions for thoracic surgery clinical practice in non-epidemic area during and after the epidemic of COVID-19 were provided, to help all the thoracic surgery patients receive active and effective treatment.

[Feasibility of echocardiography-guided repeated intraventricular blood sampling in mice].

Objective: To investigate the feasibility of echocardiography-guided closed-chest repeated intraventricular blood sampling in mice, and to clarify the maximum blood volume that can be collected by this method, and whether the method can be used for long-term repeated blood collection in mice. Methods: Twenty-four male C57BL/6J mice (10-14 weeks old) were divided into the terminal experiment group (n=4, for investigating the maximum blood amount that could be sampled at one time), the repeated 0.5 ml blood collection group (n=10, sampling 0.5 ml whole blood each time, once every two days for consecutive 4 weeks), and the repeated 0.75 ml blood collection group (n=10, sampling 0.75 ml whole blood each time, once every two days for consecutive 4 weeks). High-frequency echocardiography was used to display the largest section of the left ventricle, guiding the insulin syringe needle through the thorax into the left ventricle for blood collection. In the repeated 0.5 ml blood collection group, echocardiography was used to detect the cardiac structure and function before blood collection, three minutes after blood collection, and one week after the last (the 14th) blood collection. Results: We successfully performed echocardiography-guided closed-chest intraventricular blood sampling, with an average operating time (88±19)s per mouse, and a maximum blood volume (1.43±0.11)ml per mouse. In the repeated 0.5 ml blood collection group, heart rate, left ventricular ejection fraction, left ventricular fractional shortening, left ventricular end-diastolic dimension and left ventricular posterior wall end-diastolic thickness remained uncganged before the first blood collection and after 4 weeks of repeated blood collection (all P>0.05). No death in the repeated 0.5 ml blood collection group. However, in the 0.75 ml blood collection group, two mice died before the end point. Conclusions: The echocardiography-guided closed-chest intraventricular blood sampling is a safe, minimally invasive, convenient and efficient method, and can be used repeatedly for long-term blood collection in mice.

A serine protease homologue Bombyx mori scarface induces a short and fat body shape in silkworm.

Body shape is one of the most prominent and basic characteristics of any organism. In insects, abundant variations in body shape can be observed both within and amongst species. However, the molecular mechanism underlying body shape fine-tuning is very complex and has been largely unknown until now. In the silkworm Bombyx mori, the tubby (tub) mutant has an abnormal short fat body shape and the abdomen of tub larvae expands to form a fusiform body shape. Morphological investigation revealed that the body length was shorter and the body width was wider than that of the Dazao strain. Thus, this mutant is a good model for studying the molecular mechanisms of body shape fine-tuning. Using positional cloning, we identified a gene encoding the serine protease homologue, B. mori scarface (Bmscarface), which is associated with the tub phenotype. Sequence analysis revealed a specific 312-bp deletion from an exon of Bmscarface in the tub strain. In addition, recombination was not observed between the tub and Bmscarface loci. Moreover, RNA interference of Bmscarface resulted in the tub-like phenotype. These results indicate that Bmscarface is responsible for the tub mutant phenotype. This is the first study to report that mutation of a serine protease homologue can induce an abnormal body shape in insects.

[Exploring a new method for superimposition of pre-treatment and post-treatment mandibular digital dental casts in adults].

OBJECTIVE: To explore a cone beam computed tomography (CBCT)-independent method for mandibular digital dental cast superimposition to evaluate three-dimensional (3D) mandibular tooth movement after orthodontic treatment in adults, and to evaluate the accuracy of this method. METHODS: Fifteen post-extraction orthodontic treatment adults from the Department of Orthodontics, Peking University School and Hospital of Stomatology were included. All the patients had four first premolars extracted, and were treated with straight wire appliance. The pre- and post-treatment plaster dental casts and craniofacial CBCT scans were obtained. The plaster dental casts were transferred to digital dental casts by 3D laser scanning, and lateral cephalograms were created from the craniofacial CBCT scans by orthogonal projection. The lateral cephalogram-based mandibular digital dental cast superimposition was achieved by sequential maxillary dental cast superimposition registered on the palatal stable region, occlusal transfer, and adjustment of mandibular rotation and translation obtained from lateral cephalogram superimposition. The accuracy of the lateral cephalogram-based mandibular digital dental cast superimposition method was evaluated with the CBCT-based mandibular digital dental cast superimposition method as the standard reference. After mandibular digital dental cast superimposition using both methods, 3D coordinate system was established, and 3D displacements of the lower bilateral first molars, canines and central incisors were measured. Differences between the two superimposition methods in tooth displacement measurements were assessed using the paired t-test with the level of statistical significance set at P<0.05. RESULTS: No significant differences were found between the lateral cephalogram-based and CBCT-based mandibular digital dental cast superimposition methods in 3D displacements of the lower first molars, and sagittal and vertical displacements of the canines and central incisors; transverse displacements of the canines and central incisors differed by (0.3±0.5) mm with statistical significance. CONCLUSION: The lateral cephalogram-based mandibular digital dental cast superimposition method has the similar accuracy as the CBCT-based mandibular digital dental cast superimposition method in 3D evaluation of mandibular orthodontic tooth displacement, except for minor differences for the transverse displacements of anterior teeth. This method is applicable to adult patients with conventional orthodontic treatment records, especially the previous precious orthodontic data in the absence of CBCT scans.

[Application of transperineal pelvic floor ultrasonography in the diagnosis of female stress urinary incontinence].

Objective: To explore the application of transperineal pelvic floor ultrasonography in the diagnosis of female stress urinary incontinence(SUI). Methods: From March 2017 to December 2017, 60 patients diagnosed with SUI by department of gynecology, Xiangya Hospital of Central South University were selected as the case group, and 30 cases of normal women in the same period were selected as the control group. All subjects in both groups were examined by transperineal pelvic floor ultrasonography, that is, to be measured the bladder neck descent(BND), the urethral inclination angle(UIA), the posterior urethrovesical angle(PUVA) and the levator hiatus area(LHA) in resting state and during Valsalva maneuver. Results: (1)The differences in the measured values of the two groups were statistically significant(P<0.05). (2)The receiver operating characteristic curve(ROC) was used to find the cut-off values of SUI: when BND>31.5 mm; in Valsalva state, UIA>33.5°, PUVA>150.5° and LHA>20.6 cm2, with their sensitivity of 77.6%, 71.4%, 68.3% and 61.4%, respectively; the specificity of 68.9%, 74.6%, 73.9% and 78.0%, respectively. The area under the curve(AUC) were 0.753, 0.812, 0.721 and 0.712, respectively, when combined analysis of these indexes, reaching to 0.912. Conclusions: (1) Transperineal pelvic floor ultrasonography has a certain diagnostic value for SUI. (2)Combined analysis of various ultrasonic parameters can significantly improve the diagnostic efficiency of SUI.

Ultrabithorax and abdominal-A specify the abdominal appendage in a dosage-dependent manner in silkworm, Bombyx mori.

In insects, there is a considerable diversity in leg distribution on the body, including number, segmental arrangement, morphological identity and consequent function, but the genetic basis for these differences is not well understood. Here by positional cloning, we showed that a ~355 kb region, including Bombyx mori Ultrabithorax (BmUbx) and abdominal-A (Bmabd-A), was responsible for the silkworm mutant Kh-extra-crescents-like (EKh-l) that displayed additional thoracic limb-like legs on the first abdominal segment (A1) and occasionally on the second abdominal segment (A2). We found that BmUbx gene was downregulated at both messenger RNA level and protein level in EKh-l embryo, while its expression domain in the EKh-l embryo was almost the same as that in the wild type. Whereas Bmabd-A was upregulated at both levels and was ectopically overexpressed on the supernumerary leg-bearing segments in EKh-l. Compared with the previously reported Ecs-l mutant in which increased expression of both BmUbx and Bmabd-A gave rise to ectopic proleg-like appendages on the same segments, we propose that overexpressed Bmabd-A gene is capable to promote the outgrowth of extra leg appendages on A1 and A2 segments, whereas BmUbx gene is required to specify accurate morphologies of the ectopic legs in a dosage-dependent manner in silkworm. These results provide insights into how these hox genes regulate the leg morphologic diversity on the same segments.

Allergic inflammation is exacerbated by allergen-induced type 2 innate lymphoid cells in a murine model of allergic rhinitis.

BACKGROUND: Group 2 innate lymphoid cells (ILC2s) represent a new innate effector leukocyte population that mediates type-2 immune response. However, the contribution of ILC2s to allergic rhinitis (AR) is currently not well defined. OBJECTIVE: To evaluate the potential existence and function of allergen-induced ILC2s in the experimental AR. METHODS: We established a murine model of AR using ovalbumin (OVA) and aluminium hydroxide. The OVA-induced ILC2s were sorted and purified from the mouse nasal-associated lymphoid tissue (NALT). Then, we assessed ILC2s responses to mouse recombinant interleukin (rmIL)-25, anti-IL17RB antibody and CC chemokine ligand (CCL) 25 in the culture. After that, we adoptively transferred the NALT-derived ILC2s alone or plus rmIL-25 or anti-IL17RB antibody to the murine model of AR to investigate their role in the nasal allergic inflammation. RESULTS: We showed that ILC2s could be induced by OVA in the NALT of AR model. They were induced to secrete IL-5 and IL-13 by rmIL-25, and blocking of IL17RB contributed to the decreased production of these cytokines in the culture. We found that CCL25 induced the NALT-derived ILC2s migration through CC chemokine receptor 9 on ILC2s in vitro. Numbers of sneezing and nasal rubbing as well as counts of invasive eosinophils were all enhanced after the adoptive transfer of cultured ILC2s in vitro. The expressions of IL-5, IL-13, IL-25 and CCL25 in the NLF of allergic mice were also increased. CONCLUSION: These findings show that ILC2s play a proinflammatory role in the murine AR model, and also highlight ILC2s as a new target in the future AR therapy.

[Clinical outcome and high risk factor for residual lesion analysis of HSIL half a year after loop electrosurgical excision procedure: a clinical study of 1 502 cases].

Objective: To analyze clinical outcome of high-grade squamous intraepithelial lesion (HSIL) half a year after loop electrosurgical excision procedure (LEEP) and explore the high risk factor of residual cervical HSIL. Methods: The retrospective study was carried out on 1 502 patients who underwent LEEP, with HSIL in the LEEP histopathology from January 2011 to December 2013 at Obstetrics and Gynecology Hospital of Fudan University to confer the difference between residual group and non-residual group after 6 months of the leep conization. Patients were followed with ThinPrep cytologic test (TCT), high risk HPV (HR-HPV) test, colposcopy guided biopsy (CBD) and endocervical curettage (ECC). The high risks of residual cervical HSIL was analyzed. Results: Among 1 502 cases, 48 (3.20%, 48/1 502) cases suffered HSIL residual disease. Forty cases were diagnosed by CBD, 4 cases were diagnosed by ECC. The other 4 cases were both positive in CBD and ECC. Residul rate were different among different age groups. The residual rate was higher in the age ≥50 years old compared to the age below 50 [9.70% (16/165), 2.39% (32/1 337); χ(2)=25.33, P<0.01]. For post-LEEP specimens, both circumference (2.5, 2.8 cm; Z=-3.17, P<0.01) and width [0.6, 0.6 cm; Z=-2.88, P<0.01) were less in HSIL lesion residual group than those in non-residual group, though length showed no obvious difference [1.5, 1.5 cm; Z=-1.55, P>0.05) . The residual rate of leep positive margin was obviously higher than that in the negative margin group [6.77% (18/266) vs 2.43% (30/1 236) ; χ(2)=13.30, P<0.01]. Different positive margin had diverse residual rate, as positive endocervical margin was 16.07% (9/56), positive margin undetermined was 7.29%(7/96) and positive ectocervical margin was 3.33%(4/120). Both positive endocervical margin and positive margin undetermined had a higher residual rate than residual rate (χ(2)=26.99, P<0.01; χ(2)=4.24, P<0.05). Abnormal cytology showed higher residual rate than the non-residual with significant difference [6.00% (6/100) vs 1.29% (14/1 083) , χ(2)=9.50, P<0.01]. In terms of the post-LEEP HR-HPV test follow-up, HR-HPV positive's residual rate was higher than that in the negative group [2.91% (6/206) vs 0.96% (7/727)], while there was no statistical significance (χ(2)=3.10, P>0.05). Multivariate logistic analysis showed that abnormal cytology in 6 month's follow-up post-LEEP conization was an independent risk factor on residual lesion (OR=3.75, P<0.05). Conclusions: Patient with age ≥50 years old and positive endocervical margin are high risk factors for the residual HSIL lesion after LEEP conization,especially for abnormal cytology during follow up is independent risk factor for residual lesion. Colposcopy directed biopsy and (or) ECC still play an indispendsable role in finding the HSIL residual lesion.

Morphological characterization and molecular mapping of an irradiation-induced Speckled mutant in the silkworm, Bombyx mori.

Speckled (Spc), an X-ray-induced lethal mutant of Bombyx mori, exhibits a mosaic dark-brown-spotted larval epidermis in both sexes and egg-laying problems only in females. Here, we report the morphological characterization and molecular mapping of the Spc mutant. Morphological investigations revealed that the epidermal ultrastructure of the small, dark-brown spots was more dense than that of the white regions in both Spc/+ mutants and wild type, and that the lethality of the Spc/Spc mutants occurred during early embryogenesis. Furthermore, the ovarioles and ovipositor were disconnected in approximately 85.5% of Spc/+ females, a further 2.5% had a connection between the ovarioles and ovipositor that was too narrow to lay eggs. The remaining females showed a normal connection similar to that of the wild type. We successfully narrowed down the location of the Spc mutation to a region on chromosome 4 that was ∼1041 kb long. Gene-prediction analysis identified 25 candidate genes in this region. Chromosome structure analysis indicated that a ∼305 kb deletion was included in the mapping region. Temporal and spatial reverse transcription PCR (RT-PCR) analysis showed that several genes in the mapped region are associated with the Spc mutant. Although the genes responsible for the Spc mutation were not definitively identified, our results further the current understanding of the complex mechanism underlying the multiple morphological defects in Spc mutants.

Cyclic adenosine monophosphate-protein kinase A signal pathway may be involved in pulmonary aquaporin-5 expression in ischemia/reperfusion rats following deep hypothermia cardiac arrest.

We investigated the effects of cyclic adenosine monophosphate-protein kinase A (cAMP-PKA) on the expression of aquaporin 5 (AQP5) in ischemia/reperfusion (I/R) rats following deep hypothermia cardiac arrest. Wistar rats were randomly divided into: a sham control group (subjected to a sham operation); an I/R group (subjected to occlusion of the bronchial arteries and the left inferior pulmonary artery); an H89 group (subjected to occlusion of the bronchial arteries and the left inferior pulmonary vein and artery, and treated with 5 mg/kg H89 for 2 days before the study); and a forskolin group (subjected to occlusion of the bronchial arteries and the left inferior pulmonary vein and artery, and treated with 5 mg/kg forskolin for 2 days before the study). Expression levels of AQP5 mRNA and protein were determined using reverse transcription-polymerase chain reaction and western blotting. Decreased expression of AQP5 was noted in the pulmonary tissues of the I/R group compared with the sham controls. Compared to that in the control group, there was a notable decrease in AQP5 expression in the I/R group. After treating with forskolin, AQP5 expression increased in the forskolin group compared with the I/R group. In the H89 group, AQP5 expression decreased compared with the I/R group. The decreased expression of AQP5 was possibly associated with acute pulmonary injury induced by I/R. The cAMP-PKA signal pathway may be involved in the expression of AQP5 in I/R rats after deep hypothermia cardiac arrest.

Phylogenetic analysis of the Mongolian gerbil (Meriones unguiculatus) from China based on mitochondrial genome.

Meriones unguiculatus (Gerbillinae, Rodentia) is widely used as an animal model of human disease. Here, we provide the first report of the complete mitochondrial genome sequence of M. unguiculatus (GenBank accession Nos. KF425526 and NC_023263). The sequence contained the conserved vertebrate pattern of 13 protein-coding genes, 2 ribosomal RNAs, 22 transfer RNAs, and 1 major noncoding region. We identified one extended termination-associated sequence and one conserved sequence block in the non-coding region. The putative origin of replication for the light strand (OL) was 35 bp long. The OL stem and adjacent sequences were highly conserved, but the loop region differed from those of other rodent species. Base composition and codon usage of the 13 protein-coding genes in M. unguiculatus were compared with those of 23 rodent species with previously sequenced mitochondrial genomes. An A+T content of 63.0% was present in M. unguiculatus; this is similar to the Murinae average (62.4 ± 0.8%) and falls between the average for Mus musculus (63.1 ± 0.1%) and Rattus sp (61.7 ± 0.4%). The AT and GC skew values of M. unguiculatus were 0.035 and -0.28, respectively, similar to those of Cricetinae species (0.057 ± 0.05 and -0.31 ± 0.05). The codon families exhibited similar abundance in all 24 species. Analysis of phylogenetic relationships with 23 other rodent species using neighbor-joining and maximum likelihood protocols and the 12 protein-coding regions on the H strand showed that M. unguiculatus should be classified as genus Meriones, sub-family Gerbillinae, family Muridae.

A composite method for mapping quantitative trait loci without interference of female achiasmatic and gender effects in silkworm, Bombyx mori.

The silkworm, Bombyx mori, is an economically important insect that was domesticated more than 5000 years ago. Its major economic traits focused on by breeders are quantitative traits, and an accurate and efficient QTL mapping method is necessary to explore their genetic architecture. However, current widely used QTL mapping models are not well suited for silkworm because they ignore female achiasmate and gender effects. In this study, we propose a composite method combining rational population selection and special mapping methods to map QTL in silkworm. By determining QTL for cocoon shell weight (CSW), we demonstrated the effectiveness of this method. In the CSW mapping process, only 56 markers were used and five loci or chromosomes were detected, more than in previous studies. Additionally, loci on chromosomes 1 and 11 dominated and accounted for 35.10% and 15.03% of the phenotypic variance respectively. Unlike previous studies, epistasis was detected between loci on chromosomes 11 and 22. These mapping results demonstrate the power and convenience of this method for QTL mapping in silkworm, and this method may inspire the development of similar approaches for other species with special genetic characteristics.

Marker-assisted selection in breeding silkworm strains with high tolerance to fluoride, scaleless wings, and high silk production.

In the silkworm (Bombyx mori), tolerance to fluoride and scaleless wings are controlled by the dominant gene Dtf (dominant tolerance to fluoride) and recessive gene nlw (no Lepidoptera wings), respectively, and these genes have been mapped by using simple sequence repeat and sequence tag site markers. Marker-assisted evaluation and selection of silkworms with fluoride tolerance and scaleless wings were used for predicting fluoride resistance and scaleless wings in backcrossed animals. A silkworm strain was bred using this method, and its economic characteristics were found to be similar to those of commercial silkworms. These methods will therefore be useful for silkworm breeding programs and in screening for two or more characteristics of interest for segregating populations.