Investigation of the Oviductal Glycoprotein 1 (OVGP1) Gene Associated with Embryo Survival and Development in the Rabbit1

Investigation of the oviductal glycoprotein 1 (OVGP1) gene associated with embryo survival and development in the rabbit1

M. L. García,*2 R. Peiró,† M. J. Argente,* M. Merchán,‡ J. M. Folch,‡ A. Blasco,† and M. A. Santacreu†

*Departamento de Tecnología Agroalimentaria, Universidad Miguel Hernández de Elche, 03312, Orihuela, Spain; †Instituto de Ciencia y Tecnología Animal, Universidad Politécnica de Valencia, PO Box 22012, 46071, Valencia, Spain; and ‡Departament de Ciència Animal i dels Aliments, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain

ABSTRACT: An association study was performed in embryo survival and a similar embryonic stage of devel- rabbits between early embryo survival and development, opment at 48 h of gestation. However, at 72 h of ges- and the nonconservative SNP 12944C>G located in tation, the GG genotype showed greater early embryo exon 11 and the triallellic microsatellite [(GT)15T(G)5, survival than the CC genotype (0.56 embryos) and their (GT)14T(G)5, and (GT)11T(G)7)] located in the promot- embryos presented less embryonic development. Analy- er region of the oviductal glycoprotein 1 (OVGP1) gene. sis of the microsatellite was performed to ascertain the We analyzed an F2 cross of 2 lines of rabbits divergently presence or absence of the allele (GT)14T(G)5. At both selected for uterine capacity. A total of 172 and 159 stages of gestation, the (GT)14T(G)5/(GT)14T(G)5 gen- females were slaughtered at 48 and 72 h of gestation, otype showed greater early embryo survival (0.94 and respectively, to determine whether OVGP1 influences 1.54 embryos at 48 and 72 h of gestation, respectively) ovulation rate, fertilization rate, early embryo survival, and less embryonic development than the homozygous and embryonic stage of development. The results of the genotypes without the allele (GT)14T(G)5. SNP indicated that all genotypes showed similar early Key words: association study, embryo survival and development, oviductal glycoprotein 1 (OVGP1), rabbit

INTRODUCTION At present, a limited number of genes with large or moderate effects on litter size and its components Litter size is important for reducing the cost of pro- have been associated with SNP in multiparous species ducing rabbit meat, and much effort has been put into (Rothschild et al., 2007). The oviductal glycoprotein improving it by direct or indirect selection (Blasco et 1 (OVGP1) gene is a candidate gene for early prena- al., 1994). Ovulation rate (OR) and prenatal survival tal survival because OVGP1 is mainly expressed in the influence litter size in pigs, rabbits, and mice (see Blas- rabbit oviduct (Merchán et al., 2007). In other species co et al., 1993, for a review). In rabbits, early prenatal (i.e., sheep and cattle), the OVGP1 protein is also syn- survival has been shown to have an important influence thesized in the early stage of gestation (Nancarrow and on litter size; Torres et al. (1987) reported that em- Hill, 1995), and it plays an important role in fertiliza- bryo survival and development before 96 h of gestation tion and early cleavage-stage embryonic development in was responsible for the difference found in litter size several livestock species (Buhi, 2002; Killian, 2004). between 2 different rabbit lines. A divergent selection In rabbits, an SNP has been found in OVGP1, pro- experiment on uterine capacity also showed a difference ducing an AA change. Moreover, a triallelic microsatel- in early prenatal survival (Mocé et al., 2004; Peiró et lite located in the promoter region has been reported al., 2007). (Merchán et al., 2009). These mutations were associated in the divergent lines selected by uterine capacity 1 This study was supported by Comisión Interministerial de Cien- cited before. The objective of this study was to ana- cia y Tecnología (CICYT) grants CICYT-AGL2001-3068-C03 and lyze the association of the SNP 12944C>G of exon 11 CICYT-AGL2005-07624-C03. 2 Corresponding author: [email protected] and the microsatellite located in the promoter region of Received April 14, 2009. OVPG1 with embryo survival and development at 48 Accepted January 18, 2010. and 72 h of gestation.

1597

Downloaded from jas.fass.org at Camino Polytechnic on April 14, 2010. 1598 García et al. Table 1. Data for the genotypes and traits analyzed

Item Genotype Ovulation rate 48 h of gestation 72 h of gestation

SNP12944C>G CC 121 40 50 CG 163 58 52 GG 47 21 10 Total 331 119 112

Microsatellite (GT)14T(G)5/(GT)14T(G)5 21 10 7 (GT)14T(G)5/− 135 48 46 −/− 174 62 60 Total 330 120 113

MATERIALS AND METHODS Traits

All experimental procedures involving animals were The following traits were calculated: OR, fertilization approved by the Universidad Politécnica de Valencia rate [FR; FR = (TE/TE + OO) × 100], NorE, per- Research Ethics Committee. centage of NorE [%NorE; %NorE = (NorE/NorE + AE) × 100], percentage of EM [%EM; %EM = (EM/ NorE) × 100], percentage of CM [%CM; %CM = CM/ Animals NorE × 100], and percentage of BL [%BL; %BL = (BL/NorE) × 100]. Early embryo survival (EES) was A total of 331 animals (Table 1) from an F2 popula- analyzed as NorE recovered, fitting OR as a covariate. tion were generated from a reciprocal cross of High and Low lines of a divergent selection experiment on uterine capacity described by Argente et al. (1997). Details Genotyping of the Rabbit OVGP1 on the lines, breeding schemes, and crossbreeding are in the F2 Population given by Peiró et al. (2008). Animals were housed in individual metal cages at the At least 3 mL of venous blood from the marginal experimental farm of Universidad Miguel Hernández de ear vein was collected in K3EDTA plastic tubes with a Elche. They were kept under a controlled photoperiod concentration of 1.8 mg of EDTA per 1 mL of blood. (16 h light:8 h dark) and fed a pelleted commercial The samples were stored frozen (−20°C) until assayed. diet. Genomic DNA was extracted from blood samples following the ABI Prism 6100 Nucleic Acid PrepStation protocol (Applied Biosystems, Foster City, CA). Geno- Embryo Recovery typing of the nonsilent 12944C>G SNP and the triallelic microsatellite [(GT)15T(G)5, (GT)14T(G)5, and All data were gathered in the same gestation. A total (GT)11T(G)7)] was performed following the protocol of 172 and 159 nonlactating females were slaughtered described by Merchán et al. (2009). The genotypes for 48 or 72 h postcoitum, respectively, by intravenous in- the SNP were designed as CC, CG, and GG. For the jection of sodium thiopental in a dose of 50 mg/kg of association study of the microsatellite, the genotypes BW (thiobarbital, B. Braun Medical S.A., Barcelona, were grouped based on the allele (GT)14T(G)5 because Spain). previous analyses indicated that this allele had a posi- The entire reproductive tract was removed. Ovula- tive effect on reproductive traits (Merchán et al., 2009). tion rate was estimated as the number of corpora hem- According to the presence or absence of this allele, orrhagica after slaughtering. Oviducts and uteri were the studied genotypes were grouped as (GT)14T(G)5/ separated and flushed once with 5 and 10 mL of 150 (GT)14T(G)5, (GT)14T(G)5/−, or −/− . mM ammonium bicarbonate solution at room tempera- ture. Embryo recovery and classification were carried Statistical Analysis out by 3 operators. The total numbers of embryos (TE) and oocytes (OO) were recovered and counted. Em- Table 1 shows the number of females per genotype bryos were classified as normal (NorE) or abnormal and trait used in this experiment. Ovulation rate at 48 (AE) according to the method of Hafez (2000). At 48 and 72 h of gestation was analyzed with the following h of gestation, all embryos were recovered from the ovi- model: ducts and NorE were classified as early morulae (EM) or compacted morulae (CM). At 72 h of gestation, em- y = μ + YS + FH + I + O bryos were recovered from oviducts and uterine horns ijklmno i j k l and were classified as EM, CM, or blastocysts (BL). + Gm + Sn + eijklmno,

Downloaded from jas.fass.org at Camino Polytechnic on April 14, 2010. Oviductal glycoprotein 1 and embryo survival 1599 Table 2. Mean and SD for ovulation rate (OR); normal embryos (NorE); fertilization rate (FR); percentage of NorE (%NorE); and percentages of early morulae (%EM), compacted morulae (%CM), and blastocysts (%BL)

48 h of gestation 72 h of gestation

Item OR NorE FR %NorE %EM %CM NorE FR %NorE %EM %CM %BL

Mean 12.9 11.9 98.1 99.3 13.3 86.7 11.8 97.6 99.1 12.2 72.9 14.9 SD 2.5 2.3 4.9 3.7 25.7 25.7 2.7 6.3 2.9 25.8 24.3 24.7

where YSi is the effect of year-season (with 3 levels), Rv for all the embryonic stages of development was FHj is the effect of hemorrhagic follicles (with 3 levels: established as one-third of the phenotypic SD of the 0, between 1 and 5, and 6 or more follicles), Ik is the trait, or 8%. effect of the interval between weaning and mating for In Bayesian statistics, we do not work with signifi- slaughtering (with 2 levels: until 1 mo or more than cances, but with actual probabilities (see Blasco, 2001, 1 mo), Ol is the effect of operator (with 3 levels), Gm for a comparison between classical and Bayesian meth- is the effect of OVPG1 genotype [with 3 levels: CC, ods in animal genetics) so that we can estimate, on CG, and GG for the SNP 12944C>G, or (GT)14T(G)5/ one side, the probability of a difference being greater (GT)14T(G)5, (GT)14T(G)5/−, and −/− for the micro- than an Rv, which we call the probability of relevance, satellite], Sn is the effect of the time of gestation (with Pr, or, on the other side, the probability of a differ- 2 levels: 48 and 72 h after mating), and eijklmno is the ence being, in absolute value, less than an Rv (i.e., the error. probability of both treatments being similar in biologi- Fertilization rate, EES, and embryonic stage of de- cal or economic terms), which we call the probability velopment at 48 h of gestation were analyzed using the of similarity, Ps. The latter probability allowed us to former model without the effect of time of gestation. distinguish a case in which both treatments had equal Fertilization rate, EES, and embryonic stage of devel- effects (increased Ps) from a case in which we did not opment at 72 h of gestation were analyzed using the find differences between treatments because of poor same model as before, including the effect of the pres- precision. In the latter case, both Ps and Pr would be ence or absence of embryos in the uterus. Early embryo decreased. survival at 48 and 72 h was analyzed as NorE, with OR included as a covariate. RESULTS Traits were analyzed using a Bayesian approach. Data were conditionally distributed as Table 2 shows means and SD for the traits measured. Fertilization rate was high (approximately 98%) at 48 yb,, σσ2  NXb I 2 , and 72 h of gestation. The %NorE was large, and most e ()e embryos were also classified as CM in both stages of gestation. where b contains the effects to be estimated. The Features of D between the CC and GG genotypes are known incidence matrix is X, and I is the identity ma- presented in Table 3. All Monte Carlo SE were small trix. Bounded uniform priors were used for all unknown and the Geweke Z-test did not detect a lack of conver- parameters. Marginal posterior distributions of all un- gence in any case. Marginal posterior distributions were knowns were estimated using Gibbs sampling. A chain approximately normal. of 120,000 samples was used, with a burn-in period of The homozygote genotypes had similar OR and FR 20,000. Convergence was tested using the Z-criterion of at 48 and 72 h of gestation because the difference be- Geweke, and Monte Carlo sampling errors were com- tween homozygote genotypes was small (Table 3). At puted using the time-series procedures described by 48 h of gestation, both homozygote genotypes had simi- Geyer (1992). lar EES, but they seemed to have a smaller %EM (D = Inferences were made from the estimated marginal −6.16%). At 72 h of gestation, the CC genotype showed posterior distributions of the differences (D) between less EES than the GG genotype (D = −0.56 embryos; genotypes as in the study by Peiró et al. (2008). We P = 86%). Indeed, the probability of the GG genotype proposed what we consider to be relevant values, Rv, having at least 0.5 embryos more than the CC genotype for these differences. We consider Rv = 0.5 kits and Rv was Pr = 73%. Furthermore, their embryos presented = 3.5% to be relevant differences for OR and FR, as a greater embryonic stage of development because the discussed by Peiró et al. (2008), and Rv = 0.25 embryos CC genotype showed a smaller %EM and a greater to be a relevant difference for EES because Mocé et al. %BL than the GG genotype. (2004) found that one-half the difference in the number Table 3 also shows results for the CC and CG geno- of implanted embryos in the lines that originated from types. Both genotypes had similar OR (Ps = 90%), FR our population occurred before 72 h of gestation. The (Ps = 100%), and embryo survival and development at

Downloaded from jas.fass.org at Camino Polytechnic on April 14, 2010. 1600 García et al. Table 3. Features of the estimated marginal posterior distributions of the differences (D) between different genotypes of the 12944C>G SNP of oviductal glycoprotein 1 (OVGP1) for ovulation rate (OR); fertilization rate (FR); early embryo survival (EES); and percentages of early morulae (%EM), compacted morulae (%CM), and blastocysts (%BL) at 48 and 72 h of gestation1

CC-GG CC-CG

Item D SD P, % D SD P, %

OR 0.39 0.42 83 0.01 0.28 52 48 h FR −1.77 1.28 91 −0.42 1.01 67 EES 0.03 0.34 54 0.17 0.26 73 %EM −6.16 7.28 79 5.88 5.58 85 72 h FR −3.02 2.20 91 −3.19 1.19 99 EES −0.56 0.51 86 −0.80 0.30 100 %EM −10.32 8.92 86 1.14 5.07 59 %CM 2.48 10.85 58 −6.22 6.01 85 %BL 7.60 7.25 83 5.40 4.12 90 1P, % = P(D >0) when D >0 and P(D <0) when D <0.

48 h of gestation. Nevertheless, when the traits were had a greater FR (D = 7.24%) and EES (D = 1.54 em- analyzed at 72 h of gestation, we observed that the CC bryos) than the −/− genotype. Indeed, the probability genotype had less EES (D = −0.80 embryos) than the of the (GT)14T(G)5/(GT)14T(G)5 genotype having at CG genotype. Moreover, the probability that the CG least 0.5 embryos more than the −/− genotype was genotype had at least 0.5 embryos more than the CC Pr = 90%. Regarding the embryonic stage of develop- genotype was Pr = 96%. However, similar embryonic ment, the (GT)14T(G)5/(GT)14T(G)5 genotype showed stages of development were observed. a greater %EM (D = 9.13%) and a smaller %BL (D = Table 4 shows the results of the estimated D between −20.53%). the (GT)14T(G)5/(GT)14T(G)5 and −/− genotypes. The (GT)14T(G)5/(GT)14T(G)5 genotype had an OR The (GT)14T(G)5/(GT)14T(G)5 genotype had a greater similar to the heterozygote genotype (Table 4). The OR than the −/− genotype. At 48 h of gestation, the (GT)14T(G)5/(GT)14T(G)5 genotype showed a de- (GT)14T(G)5/(GT)14T(G)5 genotype had greater EES creased FR, although the difference was relatively small. (D = 0.94 embryos) than the −/− genotype. Further- Although the (GT)14T(G)5/(GT)14T(G)5 genotype had more, the (GT)14T(G)5/(GT)14T(G)5 genotype showed less EES at 48 h of gestation than the heterozygote less embryonic development than the −/− genotype genotype, the homozygote genotype showed greater because the %EM was greater (D = 27.52%). At 72 h EES at 72 h of gestation (0.89 embryos). Moreover, the of gestation, the (GT)14T(G)5/(GT)14T(G)5 genotype probability of the homozygote genotype having at least

Table 4. Features of the estimated marginal posterior distributions of the differences (D) between different genotypes of the microsatellite of oviductal glycoprotein 1 (OVGP1) for ovulation rate (OR); fertilization rate (FR); early embryo survival (EES); and percentages of early morulae (%EM), compacted morulae (%CM), and blastocysts (%BL) at 48 and 72 h of gestation1

[(GT)14T(G)5/(GT)14T(G)5] − (−/−) [(GT)14T(G)5/(GT)14T(G)5] − [(GT)14T(G)5/−]

Item D SD P, % D SD P, %

OR 1.47 0.84 96 0.10 0.53 58 48 h FR 2.17 2.84 78 −3.16 1.63 97 EES 0.94 0.73 90 −0.34 0.41 76 %EM 27.52 26.06 85 −12.86 15.94 79 72 h FR 7.24 3.91 96 3.10 3.38 55 EES 1.54 0.97 94 0.89 0.65 90 %EM 9.13 16.85 71 −5.30 11.62 66 %CM 11.89 19.50 73 2.72 14.03 58 %BL −20.53 13.67 93 2.63 9.48 60 1P, % = P(D >0) when D >0 and P(D <0) when D <0.

Downloaded from jas.fass.org at Camino Polytechnic on April 14, 2010. Oviductal glycoprotein 1 and embryo survival 1601 0.5 embryos more than the heterozygote genotype was onic stage of development (Hill et al., 1996a,b; Kouba Pr = 82%. At both stages of gestation, both genotypes et al., 2000, in pigs). had similar embryonic stages of development. The analyzed polymorphisms, located in the promoter region of OVPG1 in rabbits, revealed a conservative DISCUSSION region homologous to that in humans. These polymorphisms are known to be close to ERE gene transactiva- We propose the OVPG1 as a candidate gene to ex- tion, the TATA-box region, and also the transcriptional plain part of the variability in EES in the rabbit. Until region (Merchán et al., 2009). In humans, several stud- 72 h of gestation, the embryos are still in the oviduct, ies have indicated that the presence of polymorphisms where the OVPG1 is mainly expressed (Merchán et al., in the promoter region can modify gene expression be- 2007). cause these polymorphisms can alter the transcription The full sequence and structure of the rabbit OVPG1 factors, the chromatin structure, or the DNA conforma- was reported by Merchán et al. (2007). A SNP 12944C>G tion (Kashi et al., 1997; Iglesias et al., 2004; Szalai et associated with the lines divergently selected by uterine al., 2005; Buckland, 2006). capacity was found in exon 11, determining the AA In conclusion, the GG genotype of the SNP of exon change Arg468Gly. Moreover, a triallelic microsatellite 11 and the (GT)14T(G)5/(GT)14T(G)5 genotype of the located in the promoter region was reported (Merchán microsatellite located in the promoter region of OVPG1 et al., 2009). showed a favorable association with EES and less em- In this paper, we study the association of this gene bryo development in the first stages of gestation. More with the EES and early embryo development at 48 and research is needed to confirm the association of these 72 h of gestation. The GG genotype had greater EES polymorphisms in commercial lines. (0.56 embryos) and less development at 72 h of gestation than the CC genotype. The difference found be- LITERATURE CITED tween homozygote genotypes for the SNP at 72 h of gestation is relevant, representing 21 and 40% of the Argente, M. J., M. A. Santacreu, A. Climent, G. Bolet, and A. Blasco. 1997. Divergent selection for uterine capacity in rabbits. phenotypic SD of EES and %EM, respectively. Mer- J. Anim. Sci. 75:2350–2354. chán et al. (2009) found that the GG genotype had 0.83 Blasco, A. 2001. The Bayesian controversy in animal breeding. J. more implanted embryos and 0.58 more kits born alive Anim. Sci. 79:2023–2046. than the CC genotype in the same population. A large Blasco, A., M. J. Argente, C. S. Haley, and M. A. Santacreu. 1994. part of the difference at implantation was then found at Relationships between components of litter size in unilaterally ovariectomized and intact rabbit does. J. Anim. Sci. 72:3066– 72 h of gestation. Similar results were found when the 3072. microsatellite was analyzed, representing 57 and 83% of Blasco, A., J. P. Bidanel, G. Bolet, C. S. Haley, and M. A. Santa- the phenotypic SD of EES and %BL, respectively. At creu. 1993. The genetics of prenatal survival of pigs and rab- this stage of gestation, it seems that the heterozygote bits: A review. Livest. Prod. Sci. 36:153–162. genotype had EES similar to the GG genotype and that Buckland, P. R. 2006. The importance and identification of regula- tory polymorphism and their mechanisms of action. Biochim. their embryos showed less embryonic development. No Biophys. Acta 1762:17–28. clear pattern of results was observed when the micro- Buhi, W. C. 2002. Characterization and biological roles of oviduct- satellite was analyzed. specific, oestrogen-dependent glycoprotein. Reproduction These polymorphisms were found in a divergent se- 123:355–362. lection experiment on uterine capacity in the rabbit, Geyer, C. M. 1992. Practical Markov chain Monte Carlo (with discussion). Stat. Sci. 7:467–511. as described by Merchán et al. (2009). However, the Hafez, E. S. E. 2000. Preservation and cryopreservation of gametes line selected to decrease uterine capacity was associated and embryos. Pages 431–442 in Reproduction in Farm Animals. with the polymorphisms with greater EES. Lippincott Williams and Wilkins, Baltimore, MD. Little information is available on the effect of OVGP1 Hill, J. L., S. K. Walker, G. H. Brown, and C. D. Nancarrow. 1996a. on EES and early embryo development. Yong et al. The effects of an estrus-associated oviductal glycoprotein on the in vitro fertilization and development of ovine oocytes matured (2002) suggested that early embryo development is in- in vitro. Theriogenology 46:1379–1388. hibited when the C-terminal region of the oviductin Hill, J. L., S. K. Walker, G. H. Brown, and C. D. Nancarrow. 1996b. protein is blocked. Because the SNP 12944C>G was The effects of an ovine oviductal estrus-associated glycoprotein located in exon 11 and it produces an AA change that on early embryo development. Theriogenology 46:1367–1377. is located in the C-terminal region of the protein, this Iglesias, A. R., E. Kindlund, M. Tammi, and C. Wadelius. 2004. Some microsatellites may act as novel polymorphic cis-regu- SNP could modify embryo survival and development. latory elements through transcription factor binding. Gene On the other hand, the microsatellite was located in 341:149–165. the promoter region, and it could change OVGP1 and Kashi, Y., D. King, and M. Soller. 1997. Simple sequence repeats as protein expression. Results from an in vitro experiment a source of quantitative variation. Trends Genet. 13:74–78. with sheep showed an improvement in embryo survival Killian, G. J. 2004. Evidence for the role of oviduct secretions in sperm function, fertilization and embryo development. Anim. when the concentration of oviductin was augmented Reprod. Sci. 82–83:141–153. (Hill et al., 1996a). Contradictory results were obtained Kouba, A. J., L. R. Abeydeera, I. M. Alvarez, B. N. Day, and W. when oviductin concentration was related to the embry- C. Buhi. 2000. Effects of the porcine oviduct-specific glycopro-

Downloaded from jas.fass.org at Camino Polytechnic on April 14, 2010. 1602 García et al. tein on fertilization, polyspermy, and embryonic development in gle-nucleotide polymorphism in the progesterone receptor gene vitro. Biol. Reprod. 63:242–250. and its association with reproductive traits in rabbits. Genetics Merchán, M., R. Peiró, M. J. Argente, M. A. Santacreu, M. L. 180:1699–1705. García, A. Blasco, and J. M. Folch. 2009. Effects of the rabbit Peiró, R., M. A. Santacreu, A. Climent, and A. Blasco. 2007. Early oviductal glycoprotein 1 (OVGP1) gene on components of litter embryonic survival and embryo development in two divergent size. Anim. Genet. 40:756–758. lines selected for uterine capacity. J. Anim. Sci. 85:1634– Merchán, M., R. Peiró, M. A. Santacreu, O. Francino, and J. M. 1639. Folch. 2007. Rabbit oviductal glycoprotein 1 gene: Genomic or- Rothschild, M. F., Z. Hu, and Z. Jiang. 2007. Advances in QTL ganization polymorphism analysis and mRNA expression. Mol. mapping in pigs. Int. J. Biol. Sci. 3:192–197. Reprod. Dev. 74:687–693. Szalai, A. J., J. Wu, E. M. Lange, M. A. McCrory, C. D. Langefeld, Mocé, M. L., M. A. Santacreu, A. Climent, and A. Blasco. 2004. A. Williams, S. O. Zakharkin, V. George, D. B. Allinson, G. The effect of divergent selection for uterine capacity on fetal S. Cooper, F. Xie, Z. Fan, J. C. Edberg, and R. P. Kimberly. and placental development at term in rabbits: Maternal and 2005. Single-nucleotide polymorphisms in the C-reactive pro- embryonic genetic effects. J. Anim. Sci. 82:1046–1052. tein (CRP) gene promoter that affect transcription factor bind- Nancarrow, C. D., and J. L. Hill. 1995. Oviduct proteins in fer- ing, alter transcriptional activity, and associate with differences tilization and early embryo development. J. Reprod. Fertil. in baseline serum CRP level. J. Mol. Med. 83:440–447. 49(Suppl.):3–13. Torrès, S., F. Hulot, M. Meunier, and C. Sevellec. 1987. Compara- Nui, B. Y., Y. Z. Xiong, F. E. Li, S. W. Jiang, C. Y. Deng, S. H. tive study of preimplantation development and embryonic loss Ding, W. H. Guo, M. G. Lei, R. Zheng, B. Zuo, D. Q. Xu, in two rabbit strains. Reprod. Nutr. Dev. 27:707–714. and J. P. Li. 2006. Oviduct-specific glycoprotein 1 locus is as- Yong, P., Z. Gu, J. P. Luo, J. R. Wang, and J. K. Tso. 2002. An- sociated with litter size and weight of ovaries in pigs. Asian- tibodies against the C-terminal peptide of rabbit oviductin in- australas. J. Anim. Sci. 19:632–637. hibit mouse early embryo development to pass 2-cell stage. Cell Peiró, R., M. Merchán, M. A. Santacreu, M. J. Argente, M. L. Res. 12:69–78. García, J. M. Folch, and A. Blasco. 2008. Identification of sin-

Downloaded from jas.fass.org at Camino Polytechnic on April 14, 2010.