Feedback loop promotes sucrose accumulation in cotyledons to facilitate sugar-ethylene signaling-mediated, etiolated-seedling greening.

De-etiolation is indispensable for seedling survival and development. However, how sugars regulate de-etiolation and how sugars induce ethylene (ET) for seedlings to grow out of soil remain elusive. Here, we reveal how a sucrose (Suc) feedback loop promotes de-etiolation by inducing ET biosynthesis. Under darkness, Suc in germinating seeds preferentially induces 1-amino-cyclopropane-1-carboxylate synthase (ACS7; encoding a key ET biosynthesis enzyme) and associated ET biosynthesis, thereby activating ET core component ETHYLENE-INSENSITIVE3 (EIN3). Activated EIN3 directly inhibits the function of Suc transporter 2 (SUC2; a major Suc transporter) to block Suc export from cotyledons and thereby elevate Suc accumulation of cotyledons to induce ET. Under light, ET-activated EIN3 directly inhibits the function of phytochrome A (phyA; a de-etiolation inhibitor) to promote de-etiolation. We therefore propose that under darkness, the Suc feedback loop (Suc-ACS7-EIN3-|SUC2-Suc) promotes Suc accumulation in cotyledons to guarantee ET biosynthesis, facilitate de-etiolation, and enable seedlings to grow out of soil.

Genetic Variants in ADD1 Gene and their Associations with Growth Traits in Cattle.

The α-adducin (ADD1) is a subunit of adducin which is a cytoskeleton heterodimeric protein. Adducin participates in oocytes chromosome meiosis of mice, prompting adducin has an effect on embryonic development. Adducin gene mutation has significantly functional change. So the present study was to identify and characterize polymorphisms within the coding region of the bovine ADD1 gene among different cattle breeds. Here, 11 novel single nucleotide polymorphisms (SNPs 1-11) were identified by DNA sequencing and polymerase chain reaction-single stranded conformational polymorphism, there were one synonymous mutation in exon 1 (SNP1); four missense mutations in exons 4, 7, and 8 (SNPs 3-6); and six mutations in introns 4, 12, 13, and 14 (SNPs 2, 7-10). The statistical analyses indicated that the some SNPs are associated with the growth traits (body length, body height, chest circumference, and hucklebone width) in Chinese Jiaxian cattle population. Our results provide evidence that polymorphisms in the ADD1 gene are associated with growth traits, and may be used for marker-assisted selection in beef cattle breeding program.

Effect of Genetic Variations within the I-mfa Gene on the Growth Traits of Chinese Cattle.

I-mfa (inhibitor of the MyoD family a) is a transcription modulator that binds to MyoD family members and inhibits their transcriptional activities. It is highly expressed in the sclerotome and plays an important role in the patterning of the somite early in development. In this study, the polymorphisms of the bovine I-mfa gene were detected by polymerase chain reaction-single stranded conformational polymorphism (PCR-SSCP) and DNA pool sequencing methods in 541 individuals from three Chinese cattle breeds. The results showed that P3 locus had two novel complete linked single nucleotide polymorphisms (NC_007324.4:g.12284A>G and g.12331T>C), resulting in a missense mutation p.S(AGC)113G(GGC) and a synonymous mutation p.H(CAT)128H(CAC), respectively. P4 locus had a novel SNP (NC_007324.4: g.16432C>A), which resulted in a nonsense mutation p.C(TGC)241X(TGA). The statistical analyses indicated that the three SNPs, are associated with the phenotypic traits in Luxi (LX), Qinchuan (QC), and Jiaxian (JX) cattle population (P < 0.05 or P < 0.01). The mutant-type variants were superior for growth traits; the heterozygote diplotype was associated with higher growth traits compared to wild-type homozygote. Our results provide evidence that polymorphisms in the I-mfa gene are associated with growth traits and may be used for marker-assisted selection in beef cattle breeding program.

Genetic Variants in SDC3 Gene are Significantly Associated with Growth Traits in Two Chinese Beef Cattle Breeds.

Identification of the genes and polymorphisms underlying quantitative traits, and understanding these genes and polymorphisms affect economic growth traits, are important for successful marker-assisted selection and more efficient management strategies in commercial cattle (Bos taurus) population. Syndecan-3 (SDC3), a member of the syndecan family of type I transmembrane heparan sulfate proteoglycans is a novel regulator of feeding behavior and body weight. The aim of this study is to examine the association of the SDC3 polymorphism with growth traits in Chinese Jiaxian and Qinchuan cattle breeds (). Four single nucleotide polymorphisms (SNPs: 1-4) were detected in 555 cows from three Chinese native cattle breeds by means of sequencing pooled DNA samples and polymerase chain reaction-single stranded conformational polymorphism (PCR-SSCP) methods. We found one SNP (g.28362A > G) in intron and three SNPs (g.30742T > G, g.30821C > T and 33418 A > G) in exons. The statistical analyses indicated that these SNPs of SDC3 gene were associated with bovine body height, body length, chest circumference, and circumference of cannon bone (P < 0.05). The mutant-type variant was superior for growth traits; the heterozygote was associated with higher growth traits compared to wild-type homozygote. Our result confirms the polymorphisms in the SDC3 gene are associated with growth traits that may be used for marker-assisted selection in beef cattle breeding programs.

Effects of single and combined genotypes of MC4R and POU1F1 genes on two production traits in Langshan chicken.

The objective of this study was to analyze the effects of single and combined genotypes of MC4R and POU1F1 genes in Chinese well-known indigenous chicken (Langshan chicken) population. Genetic variants within MC4R gene and POU1F1 gene were screened through PCR-SSCP and DNA sequencing methods. A C/T mutation at nt 944 in MC4R gene (NC_006089.2:g. 944C>T) and a G/A mutation at nt 3109 in POU1F1 gene (NC_006088.2:g. 3109 G>A) were identified. Associations between the mutations of the two genes with two production traits were analyzed. The results showed that, at MC4R locus, individuals with BB and AB genotypes had highly significantly higher body weight at 16 weeks (p < 0.01) than did those with the AA genotype. And, individuals within AA and AB genotypes had significantly higher egg numbers at 300 days (p < 0.05). At POU1F1 locus, individuals with CD genotype had higher body weight at 16 weeks and egg numbers at 300 days (p < 0.05). Furthermore, combined genotypes from these two loci were found to be associated with egg numbers at 300 days (p < 0.05). The individuals within combined genotype AB/CD had higher egg production. Therefore, variations identified within the MC4R and POU1F1genes are suitable for future use in identifying chickens with the genetic potential of higher body weight and reproductive traits, at least in the population of Langshan chickens.

The fear gene stathmin alleles generated heterosis on feed efficiency parameters in Peking ducks.

Stathmin is an inhibitor of microtubule formation, as highly expressed in the lateral nucleus (LA) of the amygdala as well as in the thalamic and cortical structures that send information to the LA about the learned and innate fear. So we assume that STMN1 genetic variation may also affect the physical activity so as to influence the Residual Feed Intake (RFI) of duck. The Single Nucleotide Polymorphisms (SNPs) in duck Stathmin gene were screened by sequencing and genotyped by restriction endonuclease Msp I, EcoR I, Xho I, Taq I, EcoR II. A total of five SNPs (c.187 -15G > A, c.187 -110T > C, c.379 -95G > A, c.379 -318C > T, c.426 C > T) were detected in duck STMN1 gene. The c.187 -15G > A is near the 3' splice site of intron 2, which has a putative effect on the STMN1 pre-mRNA secondary structures. The c.187 -15G > A genotypes had significant effect on RFI of Peking drakes (P < 0.01). Individuals with heterozygous genotypes were more productive than that with homozygous genotypes, which suggested a molecular heterosis in c.187 -15 alleles on RFI. The current study is the first step to confirm the relationship between STMN1 gene polymorphisms and RFI. Supplemental material is available for this article. Go to the publisher's online edition of Animal Biotechnology for a figure of linkage disequilibrium between SNPs and table about frequencies of haploype.

A large indel mutation of the bovine ADD1/SREBP1c gene and its effects on growth traits in some native cattle breeds from China.

Adipocyte determination and differentiation-dependent factor 1/sterol regulatory element-binding protein-1c (ADD1/SREBP1c) is a major determinant of tissue differential lipogenic capacity in mammalian and avian species. The objectives of the present study were to focus on insertion-deletion polymorphism (indel) in the bovine ADD1/SREBP1c gene, and analyzing its effect on growth traits in a sample of 1035 cattle belonging to four Chinese cattle breeds. PCR-SSCP, DNA sequencing and agarose electrophoresis methods were used. The 778 bp PCR products of ADD1/SREBP1c gene exhibited three genotypes and two alleles were revealed: W and D. Frequencies of the W allele varied from 0.8651 to 1.000. The associations of the 84 bp indel mutation of ADD1/SREBP1c gene with growth traits of 265 Nanyang cows were analyzed. The animals with genotype WD had significantly higher birth weight, body weight, average daily gain than those with genotype WW at birth, 6-, 12-, 18-, and 24-month old (P < 0.05 or P < 0.01). These results suggest that the indel mutation of bovine ADD1/SREBP1c gene may influence the growth traits in cattle.

Novel SNPs of the caprine growth hormone secretagogue receptor (GHSR) gene and their association with growth traits in goats.

Growth hormone secretagogue receptor (GHSR), a G protein-coupled receptor that binds ghrelin, plays an important role in the central regulation of pituitary growth hormone secretion, food intake, and energy homeostasis. This study analyzed polymorphism of the caprine GHSR gene as a genetic marker candidate for growth traits in goats. Two single nucleotide polymorphisms (GU014697:g.165G-->A and GU014697:g.548T-->C) were identified in exon 2 of the caprine GHSR gene by PCR-single-strand conformation polymorphism and DNA sequencing methods. Their associations with growth traits were analyzed in 313 Xuhuai goats. The results indicated that GU014697:g.548T-->C had significant effects on growth traits. Body length and body length index were significantly higher in individuals with genotype TT than CC and CT in (P < 0.05). TT individuals also tended to have better performance in other traits, such as body height and chest circumference, although there were no statistical differences (P > 0.05). This suggests that GHSR is a strong candidate gene that affects growth traits in goats.

Stearoyl-CoA desaturase (SCD) gene polymorphism in goat breeds.

There is evidence that stearoyl-CoA desaturase (SCD) is a key enzyme for lipid metabolism. Changes in enzyme activity that depends on SCD gene polymorphism and regulation could cause variations of fatty acid composition of meat and milk. We investigated genetic variability in caprine SCD, analyzing 335 animals belonging to three goat breeds by single-strand conformation polymorphism and DNA sequencing. Six single nucleotide polymorphism were identified, in intron 3 (585T-->A and 601A-->G; Ref. AF422168), intron 4 (719T-->A; AF422169), and exon 6 (690 A-->G, 718 C-->G, and 802 A-->C; AF422171). The less polymorphic SNP 601A-->G displayed variability only in Xuhuai and Boer breeds. Across breeds, the average frequency for the least frequent alleles ranged from 0.1158 to 0.2532. The three SNPs in exon 6 resulted in variations of amino acids 313 tyr --> cys, 322 phe --> leu, and 350 arg --> ser. The allelic distribution in exon 6 of Xuhuai was significantly different from Boer and Haimen.

[The polymorphism of bovine POMC gene and its association with the growth traits of Nanyang cattle].

Pro-opiomelanocortin (POMC) plays an important role on animal ingestive behavior and energy homeostasis. Genetic variation of POMC was detected by PCR-SSCP and DNA sequencing techniques in 480 individuals from seven cattle breeds (i.e., Qinchuan, Nanyang, Jiaxian Red cattle, Jinnan, Luxi, Angus, and Chinese Holstein), and association analyses were carried out to evaluate the effects of genotypes of the candidate genes on growth traits in Nanyang cattle. Three SNPs (811845 C>T, 811821 T>C and 811797 A>G, ref. NW_928357) in linkage were detected in P3 locus, which were located at the 3' flanking region of bovine POMC gene. The body weight at 6-month-old and the average daily gain of 0~6-month-old were higher in Nanyang cattle with the genotype BB than with the genotype AA (P<0.05).

Association between variants in the 5'-untranslated region of the bovine MC4R gene and two growth traits in Nanyang cattle.

Melanocortin-4 receptor (MC4R) is one of five G-protein-coupled receptors binding melanocortins that is implicated in the control of feeding behavior and energy homeostasis. Six cattle populations (n = 594), including four Chinese indigenous breeds, Chinese Holstein, and a meat type breed (Angus), were used to detect single nucleotide polymorphisms in 5'-untranslated region of MC4R gene by means of PCR-SSCP and DNA sequencing. Four linked SNPs (g.[-293C>G; -193A>T; -192T>G; -129A>G]) were identified. The g.-293C>G and g.-129A>G could be genotyped with a PCR-RFLP using TaiI in three combined genotypes (AA, AB and BB). The two linked SNPs were associated with body weight and daily gain in Nanyang aged 6 months (P < 0.05), but they had no significant effect on body weight and daily gain in Nanyang aged 24 months (P > 0.05).

The polymorphisms of bovine cocaine- and amphetamine-regulated transcripts and their associations with cattle (Bos taurus) growth traits.

We investigated the polymorphisms of bovine cocaine- and amphetamine-regulated transcripts (CART ). The coding and regulating regions of CART were screened in 7 cattle breeds by the single-stranded conformation polymorphism (SSCP) technique. The four loci (C1,C2, C3 and C4) studied were all polymorphic. Polymerase chain reaction (PCR) products representing different SSCP variants were sequenced and a total of 9 single-nucleotide polymorphisms (SNPs) were found. The associations between polymorphic loci and the growth traits of Nanyang cattle were analysed. The results indicated that genotype A1A1 of the C1 locus was associated with a higher body weight (P less than 0.05) than heterozygous A1B1. Genotype A2A2 of the C2 locus was associated with lower body weight and average daily weight gain (P < or = 0.001) than heterozygous A2B2. C3 and C4 loci had no significant effect on Nanyang cattle growth traits (P > 0.05).

[Correlations between SNP of LALBA gene and economic traits in Inner Mongolian white cashmere goat].

PCR-SSCP and DNA sequencing methods were conducted to detect single nucleotide polymorphism of alpha-lactalbumin (LALBA) gene in 452 Inner Mongolian white cashmere goats (IMWC). Correlations between SNP of goat LALBA gene and economic traits, e.g., cashmere yield, cashmere thickness, length and weight, were analyzed. The SSCP in P2 primer locus, which was caused by the point mutation M63868:g.1897T>C in the exon 3 of LALBA gene was detected. At this locus, the genotype TT and allele T were predominant in the IMWC population, which agreed with Hardy-Weinberg equilibrium. Moreover, there was a significant correlation between polymorphism of goat M63868:g.1897 locus and cashmere yield of IMWC (P=0.017). The individuals with genotype TC had more cashmere yield than those with geontype TT. Hence, genotype TC of LALBA gene can be used as a molecular marker for breeding superior cashmere yield in goat marker-assisted selection.

[Association of variations in MyoD family of genes with body measurement traits in goat].

Single nucleotide polymorphisms (SNPs) of hircine myf-5, myf-6 genes and 5'flanking region of the myoD gene (myoD 5') were analyzed by PCR-SSCP in Boer goat and Xuhuai white goat. Three genotypes were found at the myf-5 locus of Xuhuai white goat, denoted AA, AB and BB, while all of Boer goats were of AA genotype. Only AA and AB genotypes were found at myf-6 and myoD 5' loci. The effects of genotypes of myf-5, myf-6 and myoD 5'flanking region loci on body measurement traits were estimated. The results showed that genotypes at the myf-5 locus were significantly associated with hucklebone width and hucklebone width index in Xuhuai white goat (P<0.05). Genotypes at the myf-6 locus were significantly associated with withers heights and hucklebone width index in Boer goat (P<0.05), but no significant associations were found for any traits in Xuhuai white goat. The myoD 5' locus was not significantly associated with any traits in both types of goat.

[Molecular genetic characteristic of bovine HTR1B gene].

The aim of the present study was to identify and characterize polymorphisms within the coding region and the 3' flanking region of the bovine serotonin receptor 1B gene among different cattle breeds. Four DNA fragments were amplified by polymerase chain reaction and then used for polymorphism identification by SSCP. The fragments showing different SSCP patterns were sequenced. And a total of six SNPs (G205T, C507T, C546G, C744T, G816A and G942A) were detected. The SNPs were at Hardy-Weinberg equilibrium except C507T and C546G in all genetic population. The frequencies of allele 205T of Holstein were much higher than that of the other six beef cattle populations. Almost the PIC of all SNPs were not more than 0.10 except that of G205T in Holstein cows, which indicated the bovine HTR1B gene was conserved.

[Study on SNPs of GHR gene and its associations with growth traits in Qinchuan cattle].

In this paper PCR-SSCP technique was used to analyze the polymorphisms of the tenth exon of GHR gene in Qinchuan cattle. The results showed that PCR products demonstrated polymorphisms in Qinchuan cattle and the population was at Hardy-Weinberg equilibrium (P > 0.05). There were three allele gene A, B, C in this locus with the corresponding frequencies of 0.5956, 0.2905 and 0.1140. The amplified fragments of homozygosis genotype were sequenced. The result showed that there were two mutation in these fragments. Then the relationship between genotypes and productive performances was analyzed by the Least Squire Method (LSM). The results showed that some productive performances of the indi-viduals with genotype AB were higher than those of the other genotypes, and the derivation was significant among geno-types. It suggested that GHR gene may be a candidate gene responsible for growth trait in Qinchuan cattle.

[A study on the karyotype, C-banding and Ag-NORs in Rana nigromaculata].

The chromosome samples of Rana nigromaculata were prepared by peripheral blood lymphocyte cultured in vitro. Karyotype, C-banding and silver-staining nucleolus organizer regions (Ag-NORs) were observed on chromosomes samples. The result showed that: (1) the chromosome number of Rana nigromaculata is 26 (2n=26), i.e., 10 large and 16 small chromosomes, the large chromosomes are matched into 5 homologous pairs and small chromosomes are matched into 8 homologous pairs, and further indicates the karyotype of Rana nigromaculata is bi-modal; (2) Metaphases of female and male were observed separately, the chromosome of No.11 has a pronounced secondary constriction in the middle of long arms. But the position of secondary constriction in the aberrant type individuals is in the middle of long arms of the No.8; (3) it has only one obvious C-banding close to the telomere, which is located in the long arms of the No.5; (4) The chromosome No.11 is a pair of homologous chromosomes with Ag-NORs, and the position of Ag-NORs in female and male is identical.