Breed differences in the distribution of BoLA-A locus antigens in American cattle

A total of 627 cattle representing seven breeds from south central Nebraska, USA were tested for 37 BoLA antigens which behave as products of 37 distinct alleles of the class I BoLA-A locus. Four antigens were absent from all breeds tested. The other antigens showed marked and statistically significant differences in breed distribution. There was no evidence for blank (null) alleles. The number of alleles in each breed ranged from 10 to 20. The Hereford and Simmental populations tested were less polymorphic than the Angus, Brown Swiss, Charolais, Gelbvieh and Limousin populations.     

Duration of the breeding season and response to reproductive manipulation in five breeds of sheep under northern prairie conditions

The breeding season was 157, 154, <126, 210 and 217 days for Rambouillet, Columbia, Suffolk, Rambouillet x Finnish Landrace and Columbia x Finnish Landrace ewes respectively. Treatment of cyclic ewes with pregnant mare serum gonadotropin (PMSG) (500 IU), following a 12-day treatment with progestin-containing intravaginal sponges, did not affect fertility, but did decrease the time from sponge removal to estrus, (control 48.0 +/- 3.1 hr; PMSG 39.4 +/- 1.8 hr) to the preovulatory surge of LH (control 52.7 +/- 2.8 hr; PMSG 39.0 +/- 1.7 hr) and FSH (control 52.3 +/- 2.9 hr; PMSG 42.8 +/- 1.6 hr) and caused an elevation of serum LH levels prior to the preovulatory surge (control 1.25 +/- 0.18 ng/ml; PMSG 2.31 +/- 0.22 ng/ml). Exposure of the purebred ewes to 18 hours of daylight in January, decreasing by 30 minutes a week subsequently, counteracted the seasonal reduction in the number of ewes lambing following induced breeding under natural daylight in May. Prolificacy was greatest in crossbred ewes and their fertility was not affected by season. Gestation period was longer for fall-bred ewes and varied with breed.     

Cattle breed as a source of variation in embryo transfer

The records of 1596 embryo collections were retrospectively analysed to investigate the influence of breed on embryo production and pregnancy rates. The breed of the donor cow was a significant source of variation in the results of embryo transfer. Total embryo production per collection ranged between breeds from 6.0 to 16.2, number of transferable embryos from 2.8 to 6.6 and percent transferable from 37% to 68%. The percent of pregnancies per collection ranged from 2.0 to 4.0 and pregnancy rates from 37% to 75%. The percent of transferable embryos and the pregnancy rate was independent of the total embryos collected. Care should be taken when interpreting the breed differences, since the donor cows were not randomly representative of the breeds and were selected on different bases. Brangus (16.2), Simbrah (15.8) and Beefmaster (13.0) produced the most embryos. The most transferable embryos were collected from Simmentals (6.6), Brangus (6.6), Chianina (6.2), Beefmaster (6.1), Simbrah (6.1) and Saler (6.0) cows. Angus (68%) had the highest percent transferable, followed by Saler (64%), Chianina (60%), Limousin (52%) and Simmental (51%). Pregnancy rates were highest in the Herefords (75%), Saler (57%), Zebu (56%), Charolais (53%), Longhorns (52%) and Simbrah (50%). Estrus response to superovulation varied between breeds, but this did not account for all the breed differences in embryo production.     

激光诱变选育洋葱新品种

采用CO2和He-Ne两种激光的三种剂量,分别辐照两个洋葱品种的湿种子,从激光辐照洋葱的变异后代中,经8年多的选育,培育出两个红皮洋葱新品种,2004年经四川省品种委员会审定通过,定名为西葱1号(川审蔬2004020)和西葱2号(川审蔬2004021)。新品种表现出早熟、耐贮存、株形紧凑、早期抽薹率低、产量高、抗病性好等优良性状,符合生产和市场要求,可作为目前生产上种植推广品种。     

实验室繁育树鼩生理指标的检测分析

对实验室繁育的22只成年树鼩进行生理指标的检测,并与正常人参考值进行对比分析。结果显示,树鼩红细胞数8.19×1012/L,高于人参考值上限;白细胞数2.21×109/L,低于人参考值下限;肌酐16.63μmol/L,低于人参考值下限;丙氨酸氨基转移酶77.92U/L和天门冬氨酸氨基转移酶179.9U/L,都高于人参考值上限;HBsAg均为阴性0.022ng/ml±0.005。表明树鼩作为更接近人类的低等灵长类动物,适合应用于研究人类疾病的动物模型。     

湖北省三品种猪27个微卫星座位的遗传变异

采用国际动物遗传学会（ISAG）和联合国粮农组织（FAO）共同推荐的27个微卫星标记,对湖北省3个主要地方猪种（通城猪、清平猪和阳新猪）的遗传变异进行了检测。计算出各个品种的基因杂合度、各个座位的多态信息含量及品种间的遗传距离。结果表明,3个地方猪种的平均基因杂合度分别为0.7489、0.6987和0.6273,遗传多样性比较丰富;通城猪和清平猪亲缘关系较近,而两者与阳新猪亲缘关系略远。     

尖吻蝮仔蛇的人工模拟生态养殖试验

目的通过建立一个适应于尖吻蝮仔蛇生长发育的稳定的多功能生态系统的人工模拟生态养殖蛇场,以最大限度地降低仔蛇的饲料成本,从而达到降低人工养殖尖吻蝮蛇的成本。方法选取一个室外围墙式养蛇场作为试验基地。设计为适应于蛇、蛙、昆虫、蚯蚓、小杂鱼等动物生长繁衍的人工模拟生态环境,建立一个稳定的多功能蛇场生态系统,以尖吻蝮蛇100条,在试验以前随机抽取10条测量其体重和体长,并以活体动物饲料喂养法和科学饲养管理法进行试验养殖,并在进入第一、第二次冬眠前均随机抽取10条蛇仔测其体重和体长。结果本次试验与本蛇场室内人工饲养尖吻蝮仔蛇相比,不仅在体重、体长和肥满度方面均相差不大,而且仔蛇的存活率还有所提高。结论表明该人工模拟生态养殖蛇场能够满足尖吻蝮仔蛇生长发育的需要,达到了预期的目的。     

甘肃肉羊新品种选育群GDF9基因外显子2多态性及其与产羔性状关联分析

根据GenBank发布的绵羊GDF9基因外显子2的序列设计4对引物,采用PCR-SSCP技术分析GDF9基因外显子2在甘肃内羊新品种选育群羊中的单核苷酸多态性,并与产羔性状进行关联分析.结果表明,GDF9基因的扩增片段在所检测的新品种群羊中存在PCR-SSCP多态性,检测到3种基因型(AA、AB和BB),而在32只无角陶赛特母羊群中只检测到AA和AB基因型.测序结果显示,GDF9基因编码区第978位碱基发生A→G突变,但没有导致氨基酸的改变;第994位碱基发生G→A突变,导致Ⅴ变成Ⅰ(缬氨酸→异亮氨酸).新品种选育群羊产羔数的最小二乘均值关系为AB＞ AA＞ BB,统计分析结果初步表明3种基因型之间差异不显著(P＞0.05).故该区域可能不是影响新品种群羊繁殖力的功能结构区城.     

红豆杉育苗栽培及苗木生长动态

紫杉醇是当前倍受关注的抗癌新药,美国国立癌症研究所(NCI)预测,紫杉醇将成为主要的抗癌药物之一[1].其原料植物红豆杉[Taxus chinersis (Pilger) Rehd.]资源的过度开发利用,导致供求矛盾十分突出.     

Genome‐wide population structure and admixture analysis reveals weak differentiation among Ugandan goat breeds

Uganda has a large population of goats, predominantly from indigenous breeds reared in diverse production systems, whose existence is threatened by crossbreeding with exotic Boer goats. Knowledge about the genetic characteristics and relationships among these Ugandan goat breeds and the potential admixture with Boer goats is still limited. Using a medium‐density single nucleotide polymorphism (SNP) panel, we assessed the genetic diversity, population structure and admixture in six goat breeds in Uganda: Boer, Karamojong, Kigezi, Mubende, Small East African and Sebei. All the animals had genotypes for about 46 105 SNPs after quality control. We found high proportions of polymorphic SNPs ranging from 0.885 (Kigezi) to 0.928 (Sebei). The overall mean observed (H_O) and expected (H_E) heterozygosity across breeds was 0.355 ± 0.147 and 0.384 ± 0.143 respectively. Principal components, genetic distances and admixture analyses revealed weak population sub‐structuring among the breeds. Principal components separated Kigezi and weakly Small East African from other indigenous goats. Sebei and Karamojong were tightly entangled together, whereas Mubende occupied a more central position with high admixture from all other local breeds. The Boer breed showed a unique cluster from the Ugandan indigenous goat breeds. The results reflect common ancestry but also some level of geographical differentiation. admixture and f₄ statistics revealed gene flow from Boer and varying levels of genetic admixture among the breeds. Generally, moderate to high levels of genetic variability were observed. Our findings provide useful insights into maintaining genetic diversity and designing appropriate breeding programs to exploit within‐breed diversity and heterozygote advantage in crossbreeding schemes.