Search

Background In this previous work, we investigated the secondary structure changes of stretched yak hairs by deconvolution, secondary derivation, and curve fitting and determined the number of bands and their positions in order to resolve the protein spectrum of Raman spectroscopy. Objectives The secondary structure estimation and properties analysis of stretched Asian and Caucasian hair were investigated by Fourier transform infrared spectroscopy, tensile curves, and measurement of density. Methods The hairs were stretched, dried, and baked at ratios 20%, 40%, 60%, 80% and 100%. Results The analysis of the amide I band indicated that the transformation from α-helix to β-pleated structure occured during the stretching process, which could be verified from the tensile analysis. The cysteine oxide in S-O vibration area exhibited that stretching led to the breakage of the disulfide bonds. When the stretching ratio of Caucasian hair was more than a certain ratio, the fiber macromolecular structure was destroyed because Caucasian hair had finer diameter and less medulla than Asian hair. The β turn was easier to retract compared with other conformations, resulted in the content increase. The density measurements revealed that the structure of Caucasian hair was indeed more destroyed than that of Asian hair. The cuticles characterization indicated the length of scales was stretched longer and the thickness became thinner. Caucasian hair tended to collapse to form small fragments at the early stage of stretching. With the increase in stretching ratio, the scales of Caucasian hair lifted up, then flaked off and the scale interval increased accordingly. Asian hair was more easily peeled off than Caucasian hair cuticles with the increase in stretching ratio. Conclusions The secondary structure of Caucasian hair was destroyed more easily than that of Asian hair. [ABSTRACT FROM AUTHOR]

Although structural properties of the porcine reproductive system are shared by many placental mammals, some combination of these properties is unique to pigs. To explore whether genomic elements specific to pigs could potentially underlie this uniqueness, we made the first step to identify novel transcripts in two representative pig reproductive tissues by the technique of massively parallel sequencing. To automate the whole process, we built a computational pipeline, which can also be easily extended for similar studies in other species. In total, 5516 and 9061 novel transcripts were found, and 159 and 252 novel transcripts appear to be specific to pigs for the placenta and testis respectively. Furthermore, these novel transcripts were found to be enriched in quantitative trait loci ( QTL) regions for reproduction traits in pigs. We validated eight of these novel transcripts by quantitative real-time PCR. With respect to their genomic organization and their functional relationship to reproduction, these transcripts need to be further validated and explored in various pig breeds to better comprehend the relevant aspects of pig physiology that contribute to reproductive performance. [ABSTRACT FROM AUTHOR]

Summary A whole-genome association study was performed for reproductive traits in commercial sows using the PorcineSNP60 BeadChip and Bayesian statistical methods. The traits included total number born (TNB), number born alive (NBA), number of stillborn (SB), number of mummified foetuses at birth (MUM) and gestation length (GL) in each of the first three parities. We report the associations of informative QTL and the genes within the QTL for each reproductive trait in different parities. These results provide evidence of gene effects having temporal impacts on reproductive traits in different parities. Many QTL identified in this study are new for pig reproductive traits. Around 48% of total genes located in the identified QTL regions were predicted to be involved in placental functions. The genomic regions containing genes important for foetal developmental (e.g. MEF2C) and uterine functions (e.g. PLSCR4) were associated with TNB and NBA in the first two parities. Similarly, QTL in other foetal developmental (e.g. HNRNPD and AHR) and placental (e.g. RELL1 and CD96) genes were associated with SB and MUM in different parities. The QTL with genes related to utero-placental blood flow (e.g. VEGFA) and hematopoiesis (e.g. MAFB) were associated with GL differences among sows in this population. Pathway analyses using genes within QTL identified some modest underlying biological pathways, which are interesting candidates (e.g. the nucleotide metabolism pathway for SB) for pig reproductive traits in different parities. Further validation studies on large populations are warranted to improve our understanding of the complex genetic architecture for pig reproductive traits. [ABSTRACT FROM AUTHOR]

Summary Body size traits reflect the condition of body development, are always mentioned when a breed is described, and are also targets in breeding programmes. In chicken, there are several reports focused on body size traits, such as shank length, tibia length or bone traits. However, no study was carried out on chest width (CW), chest depth (CD), body slope length (BL) and head width (HW) traits. In this study, genome scans were conducted on an F2 resource population (238 F2 individuals from 15 full-sib families derived from an intercross of the White Plymouth Rock with the Silkies Fowl) to identify quantitative trait loci (QTL) associated with CW, CD, BL and HW from 7 to 12 weeks of age. In total, 21 significant or suggestive QTL were found that affected four body size traits. Four QTL reached 1% genome-wide significance level: at 297 cM on GGA3 (associated with CW at 9 weeks of age), between 155 and 184 cM on GGA1 (affecting BL traits at 9 and 10 weeks of age), at 22 cM on GGA2 (related with BL traits at 12 weeks of age) and at 36 cM on GGA1 (for HW trait at 8 weeks of age). [ABSTRACT FROM AUTHOR]

Cryptorchidism (CO) as a common developmental defect in purebred dogs causes health concerns of reduced fertility and increases risk of testicular malignancies. A total of 49 single nucleotide polymorphisms (SNPs) discovered from 20 candidate genes was investigated to analyse their associations with CO in Siberian Huskies. The sibling-transmission disequilibrium test on 38 discordant full-sibs revealed seven SNPs in the collagen type II α 1 ( COL2A1) gene were significantly (p < 0.05) or suggestively (p < 0.10) associated with CO. Further analyses showed that only one SNP (rs23358342) in this gene remained suggestively significant (p < 0.1) on a data set of full-sibs with additional related dogs, but not significant on all 156 Siberian Huskies. Based on the statistical results and the involvement of COL2A1 in the testicle development and descent, we could not exclude COL2A1 as a potential candidate gene for CO in Siberian Huskies. Further studies are necessary to clarify these results from our relatively small sample size. [ABSTRACT FROM AUTHOR]

Pacific white shrimp ( Litopenaeus vannamei) are of particular economic importance to the global shrimp aquaculture industry. However, limited genomics information is available for the penaeid species. We utilized the limited public information available, mainly single nucleotide polymorphisms (SNPs) and expressed sequence tags, to discover markers for the construction of the first SNP genetic map for Pacific white shrimp. In total, 1344 putative SNPs were discovered, and out of 825 SNPs genotyped, 418 SNP markers from 347 contigs were mapped onto 45 sex-averaged linkage groups, with approximate coverage of 2071 and 2130 cm for the female and male maps, respectively. The average-squared correlation coefficient ( r2), a measure of linkage disequilibrium, for markers located more than 50 cm apart on the same linkage group, was 0.15. Levels of r2 increased with decreasing inter-marker distance from ∼80 cm, and increased more rapidly from ∼30 cm. A QTL for shrimp gender was mapped on linkage group 13. Comparative mapping to model organisms, Daphnia pulex and Drosophila melanogaster, revealed extensive rearrangement of genome architecture for L. vannamei, and that L. vannamei was more related to Daphnia pulex. This SNP genetic map lays the foundation for future shrimp genomics studies, especially the identification of genetic markers or regions for economically important traits. [ABSTRACT FROM AUTHOR]

Shank length affects chicken leg health and longer shanks are a source of leg problems in heavy-bodied chickens. Identification of quantitative trait loci (QTL) affecting shank length traits may be of value to genetic improvement of these traits in chickens. A genome scan was conducted on 238 F2 chickens from a reciprocal cross between the Silky Fowl and the White Plymouth Rock breeds using 125 microsatellite markers to detect static and developmental QTL affecting weekly shank length and growth (from 1 to 12 weeks) in chickens. Static QTL affected shank length from birth to time t, while developmental QTL affected shank growth from time t−1 to time t. Seven static QTL on six chromosomes (GGA2, GGA3, GGA4, GGA7, GGA9 and GGA23) were detected at ages of 2, 3, 4, 5, 6, 7, 9 and 12 weeks, and six developmental QTL on five chromosomes (GGA1, GGA2, GGA4, GGA5 and GGA23) were detected for five shank growth periods, weeks 2–3, 4–5, 5–6, 10–11 and 11–12. A static QTL and a developmental QTL ( SQSL1 and DQSL2) were identified at GGA2 (between ADL0190 and ADL0152). SQSL1 explained 2.87–5.30% of the phenotypic variation in shank length from 3 to 7 weeks. DQSL2 explained 2.70% of the phenotypic variance of shank growth between 2 and 3 weeks. Two static and two developmental QTL were involved chromosome 4 and chromosome 23. Two chromosomes (GGA7 and GGA9) had static QTL but no developmental QTL and another two chromosomes (GGA1 and GGA5) had developmental QTL but no static QTL. The results of this study show that shank length and shank growth at different developmental stages involve different QTL. [ABSTRACT FROM AUTHOR]

A sufficient level of intramuscular fat (IMF) is needed to enhance consumer acceptance of pork products, and is currently receiving greater attention within swine genetic improvement programmes. An examination of previously described and novel genetic variants within candidate genes for IMF deposition was performed to evaluate potential use of genetic markers in marker-assisted selection (MAS). Biological candidate genes implicated to play a role in adipogenesis were investigated within two different lines of purebred Duroc pigs. These included MC4R, FABP3, DLK1, and TCF7L2. Significant variation in IMF within the control line was described by the MC4R genotype and a novel BsrfI single nucleotide polymorphism within the FABP3 gene. Genetic markers for DLK1 and TCF7L2 evaluated in this population are not currently recommended for selection in Duroc swine. Existence of MC4R and FABP3 mutations may be useful markers in MAS aimed at IMF improvement, provided that gene effects are segregating and the presence of an association is detected within the population. However, additional work to confirm the use of the investigated genetic markers in selection programmes is needed. [ABSTRACT FROM AUTHOR]

Litopenaeus vannamei (Pacific white shrimp) have been farmed in the Americas for many years and are growing in popularity in Asia with the development of specific pathogen-free stocks. The full genomic sequence of this species might not be available in the near future, so other tools are needed to discover the location of polymorphic sites for quantitative trait loci mapping, association studies and subsequent marker-assisted selection. Currently, 25 937 L. vannamei expressed sequence tags (ESTs) are publicly available. These sequences were manually screened, masked for tandem repeats and inputted into CAP3 for clustering. The resulting 3532 contigs were analysed for possible single nucleotide polymorphisms (SNPs) withsnpidentifier, a newly developed computer program for predicting SNPs.snpidentifier is designed for ESTs without accompanying chromatogram sequence quality information, and therefore it performs quality control checks on all data.snpidentifier sets a threshold such that the sequences used have a poor quality nucleotide (N) frequency <0.1, and it trims off the first 10 bases of every sequence to ensure higher sequence quality. For a base to be predicted as an SNP, the minor nucleotide (allele) frequency must be >0.1, it must be observed at least four times and the 15 bases on either side must exactly match the consensus sequence. Using these conservative parameters, 504 SNPs were predicted from 141 contigs for L. vannamei. A small sample of 18 individuals from three lines have been sequenced to verify prediction results and 17 of 39 (44%) of the tested SNPs have been confirmed. [ABSTRACT FROM AUTHOR]

Genome scans were conducted on an F2 resource population derived from intercross of the White Plymouth Rock with the Silkies Fowl to detect QTL affecting chicken body composition traits. The population was genotyped with 129 microsatellite markers and phenotyped for 12 body composition traits on 238 F2 individuals from 15 full-sib families. In total, 21 genome-wide QTL were found to be responsible for 11 traits, including two newly studied traits of proventriculus weight and shank girth. Three QTL were genome-wide significant: at 499 cm on GGA1 (explained 3.6% of phenotypic variance, P < 0.01) and 51 cm on GGA5 (explained 3.3% of phenotypic variance, P < 0.05) for the shank & claw weight and 502 cm on GGA1 (explained 1.4% of phenotypic variance, P < 0.05) for wing weight. The QTL on GGA1 seemed to have pleiotropic effects, also affecting gizzard weight at 490 cm, shank girth at 489 cm and intestine length at 481 cm. It is suggested that further efforts be made to understand the possible pleiotropic effects of the QTL on GGA1 and that on GGA5 for two shank-related traits. [ABSTRACT FROM AUTHOR]

A genome scan to detect quantitative trait loci (QTL) affecting body weight in chickens was conducted on 238 F2 chickens from a reciprocal cross of Silky Fowl and White Plymouth Rock using 125 microsatellite markers covering 23 autosomes and the Z chromosome. Two types of QTL were considered: static QTL (SQ) and developmental QTL (DQ). Static QTL affected the body weight from hatch to time t, and DQ affected the body weight from time t−1 to time t. Six SQ and nine DQ were detected. Of these QTL, four reached a genome-wide significance of 5% or better, with SQ1 and DQ1 being the most significant QTL. Static QTL1 was on chromosome 1 between GCT0006 and MCW0106 and explained 4.05–9.80% of the phenotypic variation in body weights from 3 to 12 weeks of age. At 9, 10 and 11 weeks, the genome-wide significance thresholds of SQ1 were <1%. Developmental QTL1 was located on chromosome 1 between MCW0168 and GCT0006, and explained 2.75% of the phenotypic variation for body weight from week 7 to 8 with a genome-wide significance level <1%. The results suggest that body weight from hatch to time t and developmental growth from time t−1 to time t may involve two different sets of genes or gene actions. [ABSTRACT FROM AUTHOR]