文山黄牛的现状与保种措施

文章阐述了文山黄牛的品种特性、现状和保种措施。文山牛保种可采用原产地活体保种,迁地活体保种和现代生物技术保种等多种方式。文山牛体型较大,性情温顺,产肉性能好、活动敏捷、结构紧凑、肌肉强健、肉品质优良、耐粗饲、适应性广、繁殖力和抗病力均较强等特点。文山牛是云南省一个地方良种,种质资源保护刻不容缓。     

群体生存力分析在大额牛保种中的应用研究

由于外来种的大量引进和杂交利用,我国地方畜禽品种资源受到严重威胁,一些品种已濒临灭绝。本文以大额牛为例,在国内外首次用群体生存力方法模拟分析该珍稀牛种资源的生存过程和系统压力及遗传等影响因素。结果表明,大额牛目前的状况很危险,按现在的生存状况,群体平均灭绝时间为52～78年。除非采取轮回交配制度、降低死亡率、减少灾害发生频率、合理的公母畜交配比例等措施。在畜禽遗传资源保护行动中,不仅需从遗传本身考虑,正确解决系统压力问题更重要。     

千万不可忽视良种黄牛的保种问题

阐述了良种牛保种的重要意义．基因的随机漂移、选择与杂交、近交是特定基因从群体中消失的主要原因，群体及其有效含量和系统选育的科学组织是保种的重要内容。最后介绍我国良种牛的保种方法及其存在的问题，并提出解决的办法。     

晋南牛的选育及保种进展

晋南牛经过长期的系统选育,已由役用型逐渐向肉用型转变。经测定,在一般育肥条件下,１６－２４月龄的屠宰率和净肉率分别为５０－５８％和４０－５０％;育肥期日增竽６３１－７８２ｇ;强度育肥的上述指标分别可达５９－６３％,４９－５３％和８５１－９６１ｇ,在保种方法上,采取区域保种,基因库保种和胚胎保种相结合,取得了良好的保种效果。     

群体生存力分析在额牛保种中的应用研究

由于外来种的大量引进和杂交利用，我国地方畜禽品种资源受到严重威胁，一些品种已濒临灭绝。本文以大额牛为例，在国内外首次用群体生存力方法模拟分析该珍稀牛种资源的生存过程和系统压力及遗传等影响因素。结果表明，大额牛目前的状况很危险，按现在的生存状况，群体平均灭绝时间为52～78年。除非采取轮回交配制度、降低死亡率、减少灾害发生频率、合理的公母畜交配比例等措施。在畜禽遗传资源保护行为中，不仅需从遗传本身考虑，正确解决系统压力问题更重要。     

晋南牛的选育及保种工作进展

晋南牛经过长期的系统选育,已由役用型逐渐向肉用型转变。经测定,在一般育肥条件下,１６—２４月龄的屠宰率和净肉率分别为５０％—５８％和４０—５０％;育肥期日增重６３１—７８２ｇ;强度育肥的上述指标分别可达５９％—６３％,４９％—５３％和８５１－９６１ｇ。在保种方法上,采取区域保种,基因库保种和胚胎保种相结合,取得了良好的保种效果。     

复州牛种群现状与保种技术探讨

本文概述复州牛保种的迫切性，并从生物技术在动物育种中的应用前景与现有技术水平出发，探讨复州牛生物技术保种的应用价值。     

渤海黑牛的保种与选育

渤海黑牛是我国仅有的一个黑毛牛品种，搞好保种与选育具有非常重要的意义。本文以渤海黑牛发展的历史及发展现状为基础，综合分析了开展渤海黑牛种质资源保护的重要性和必要性，阐述了保种与选育的技术路线、方向和方法，并就应采取的具体措施提出了建议。     

秦川牛的保种与改良

秦川牛是畜牧业生产和发展的一种珍贵的自然资源，是畜牧业生产和发展的基础和保证。本文较为系统的阐述了秦川牛保种的必要性，并对秦川牛的保种途径和方法进行了归纳。     

半野生大额牛的研究进展和保护利用现状

大额牛(Bos frontalis)在我国又叫独龙牛,是一种半野生的珍稀牛种.本文较系统地介绍大额牛的起源、繁殖特点、生产性能与杂交利用、疾病调查、迁地保护、饲养管理等研究进展,提出我国独龙牛保护、利用中存在的问题及相应对策和建议.     

大额牛冷冻精液技术的研究

本文对大额牛的射精量、精子密度、精子活力等指标进行了测定,同时对大额牛精液的冷冻稀释液、制作程序进行了较为系统的研究。结果得出,大额牛在人工饲养条件下,公牛的射精量为4.92±1.50mL、精子密度为16.79±4.5亿/mL、原精活力0.63±0.078;冷冻精液解冻活力平均可达0.3875±0.0426、冻精解冻后顶体完整率平均52.74%±5.88%,畸形率为12.95%±3.18%,精子复苏率为59.63%±3.67%,其他指标与一般黄牛基本一致。     

半野生大额牛的研究进展和保护利用现状

大额牛(Bos frontalis)在我国又叫独龙牛,是一种半野生的珍稀牛种。本文较系统地介绍大额牛的起源、繁殖特点、生产性能与杂交利用、疾病调查、迁地保护、饲养管理等研究进展,提出我国独龙牛保护、利用中存在的问题及相应对策和建议。     

Developments in prediction theories of the effective size of populations under selection

The effective population size is a key parameter in the definition of selection programs, because the magnitude of this parameter determines both the rate of inbreeding and the amount of genetic drift in the population. Prediction of the effective size of selected populations is complicated by the fact that selection has a cumulative effect on the effective size. In the present article, two basic approaches to predict the effective size of populations under selection were summarized, and the interrelation among them was clarified. Several extensions to practical situations relevant to animal breeding, such as non‐random mating, index selection and marker‐assisted selection, were also reviewed.     

云南省怒江州部分地区独龙牛毕氏肠微孢子虫感染情况及基因分型研究

为了解云南省怒江州独龙牛毕氏肠微孢子虫感染情况,从怒江州的鸠门当、古泉村、亚左洛村、茨开镇、独龙江乡分四个季度(春、夏、秋、冬)采集独龙牛粪便样本1 129份,采用分子生物学技术对其毕氏肠微孢子虫感染情况进行调查研究.结果发现,所调查地区独龙牛毕氏肠微孢子虫总感染率为1.68％(19/1 129);各地点之间感染率差异...     

基于SNP芯片监测通城猪的保种效果

旨在基于SNP芯片信息分析通城猪保种群的群体结构和遗传多样性,对保种效果进行监测。本研究利用“中芯一号”50K SNP芯片对68头通城猪的全基因组SNP进行扫描,通过以下两方面评估保种效果：1）群体结构。通过群体分层、遗传距离、亲缘关系以及公猪基因组家系等分析,研究通城猪个体间的群体结构;2）遗传多样性。估算等位基因频率、有效等位基因数、多态信息含量、多态性标记比例、杂合度、核苷酸多样性等多态性和杂合性相关参数估计遗传多样性,分析有效群体含量和连续性纯合片段（runs of homozygosity,ROH）,综合评估保种效果。结果显示：1）保种群无明显分层,遗传距离为0.27,亲缘系数为0.17;2）基因组等位基因频率为0.77,有效等位基因数为1.52,多态信息含量均值为0.31,多态性标记比例为88.28%,观测杂合度为0.32,期望杂合度为0.31;20世代前通城猪有效群体含量为105头,当前世代有效群体含量为94头;ROH共计有184个,平均ROH长度为23.71 Mb,其中28.80%的长度在15~20 Mb之间;基因组近交系数为0.04%,具较低水平的近交程度。通城猪保种群是一个没有分层的纯种群体,具有丰富的遗传多样性,得到了有效保护。     

大额牛HSL基因外显子Ⅰ部分片段的序列测定及分析

对大额牛HSL基因外显子Ⅰ部分序列进行PCR扩增、测序及氨基酸预测,并同其它牛种的资料进行了比对分析,构建了分子系统进化树。结果表明:大额牛其核苷酸序列与牦牛、普通牛、瘤牛、水牛间的同源性分别为99.6%、99.4%、99.2%、97.0%。相应的氨基酸序列大额牛与水牛的同源性为97.6%;与普通牛、瘤牛、牦牛的同源性均为99.4%,仅在第33位有1个氨基酸变异,即大额牛为异亮氨酸,而其它3个牛种均为缬氨酸,这是由该基因片段的第97位碱基发生转换(A←→G)造成的。从分子系统进化树看,瘤牛和普通牛先聚为一类,再依次与牦牛、大额牛、水牛相聚,这与传统的牛种分类结果一致。     

Population genomics provides insights into the evolution and adaptation of tree shrews (Tupaia belangeri) in China

Physiological adaptation of tree shrews (Tupaia belangeri) to changing environmental temperature has been reported in detail. However, the T. belangeri origin (mainland or island), population history, and adaptation to historical climate change remain largely unknown or controversial. Here, for the first time, we sequenced the simplified genome of 134 T. belangeri individuals from 12 populations in China and further resequenced one individual from each population. Using population genomic approaches, we first observed considerable genetic variation in T. belangeri. Moreover, T. belangeri populations formed obvious genetic structure and reflected different demographic histories; they generally exhibited high genetic diversity, although the isolated populations had relatively low genetic diversity. The results presented in this study indicate that T. b. modesta and T. b. tonquinia were separated recently and with a similar population dynamics. Second, physical barriers rather than distance were the driving factors of divergence, and environmental heterogeneity may play an important role in genetic differentiation in T. belangeri. Moreover, our analyses highlight the role of historical global climates in the T. belangeri population dynamics and indicate that the decrease of the T. belangeri population size may be due to the low temperature. Finally, we identified the olfaction-associated adaptive genes between different altitude populations and found that olfactory-related genes of high-altitude populations were selectively eliminated. Our study provides demographic history knowledge of T. belangeri; their adaption history offers new insights into their evolution and adaptation, and provides valuable baseline information for conservation measures.     

Population Structure Among Progeny-tested Bulls of the Red Dairy Breeds in Finland,Norway and Sweden

Abstract

The Icelandic cattle breed is believed to have been brought to Iceland from Norway around 1100 years ago. Since then it is thought to have been almost completely isolated and to have gone through large fluctuations in population size. Here molecular markers were used to assess the breed's genetic diversity and the current within-population genetic structure using a randomly selected unbiased sample from the population as verified by calculations of the coefficient of relationship (R). Measures of genetic diversity suggest that there is considerable diversity within the breed despite long-term isolation and the effective population size is high considering the isolation and the breeding system used in recent years. No evidence of recent bottlenecks was found and analysis of population structure suggests that the population is uniform in structure.