羊草叶绿体非编码区多态性标记筛选及群体遗传多样性

为筛选多态性丰富的羊草叶绿体非编码区片段,本研究以9个不同地理位置的羊草居群为材料,通过对12个叶绿体非编码区DNA片段测序及其序列间变异分析试图从中找出有遗传差异的叶绿体DNA(cpDNA)片段,并利用有多态性的cpDNA片段进行遗传多样性分析。结果表明,序列ndhF-rpl32、trnL-trnF、trnC-ycf6、aptI-aptH具有比较丰富的变异,可作为下一步研究野生羊草群体遗传学和谱系地理学较为理想的分子标记。在37个羊草个体4条非编码区片段的合并序列中,共检测到15种单倍型,单倍型多态性(Hd)为0.928,核苷酸多态性(Pi)为0.00101;遗传分化指数(Fst)为0.58884,基因流(Nm)为0.17,基因流较小;中性检验Tajima’s D(-1.08542)和Fu’s Fs(-5.301)均为负值,且差异不显著(P>0.10),推测羊草遵循中性进化理论,可能经历过种群扩张;AMOVA结果显示,65%的分子变异出现在居群间,35%出现在居群内;Mantel检验得到,遗传距离与地理距离具有显著相关性(r=0.449,P<0.05);居群分化值Nst 0.386(0.1865)大于Gst 0.234(0.1506),差异显著(P<0.05),表明羊草居群存在分子谱系地理结构。通过系统发育树分析得到,羊草15个单倍型分为两大分支,H2和H10聚为一支,它们与别的居群个体亲缘关系较远,其余单倍型聚为另一支;单倍型网络图显示,H2和H12、H10和H12亲缘关系较远,与系统发育树分析结果基本一致。本研究为羊草的种质资源保护、谱系地理学研究等工作奠定了基础。     

Innovative layer genetics to handle global challenges in egg production

1. In commercial layer breeding, extensive gene pools are tested and selected for market requirements which must be anticipated at least 5 years ahead. Field results confirm a continuous positive genetic trend in egg output and better feed efficiency which can be converted into land savings.

2. Animal welfare and cage-free housing dominate future needs of the market. Nesting behaviour and minimal tendency to develop feather-pecking or cannibalism without beak treatment are key trait complexes. Stronger shells for longer production cycles without moulting have to be combined with better bones.

3. No single big gene effect can be expected to control the multifactorial problem of feather-pecking. Adjusting the shape of the beak, with a heritability of .10–.25, can contribute to reducing the risk of severe cannibalism.

4. For better skeletal integrity, the assessment of bone quality in pedigree birds housed in enriched cages is done by keel bone palpation or ultrasound measurement of the humerus. Both traits show similar heritabilities in the range of .15–.30 and can be included in a balanced selection approach for performance, quality and welfare traits.

5. The combination of performance testing and genome-wide DNA marker analysis is a promising tool to generate more progress for a balanced performance and behaviour profile.     

Single step genomic evaluation for female fertility in Nordic Red dairy cattle

Joint Nordic (Denmark, Finland, Sweden) genetic evaluation of female fertility is currently based on the multiple trait multilactation animal model (BLUP). Here, single step genomic model (ssGBLUP) was applied for the Nordic Red dairy cattle fertility evaluation. The 11 traits comprised of nonreturn rate and days from first to last insemination in heifers and first three parities, and days from calving to first insemination in the first three parities. Traits had low heritabilities (0.015–0.04), but moderately high genetic correlations between the parities (0.60–0.88). Phenotypic data included 4,226,715 animals with records and pedigree 5,445,392 animals. Unknown parents were assigned into 332 phantom parent groups (PPG). In mixed model equations animals were associated with PPG effects through the pedigree or both the pedigree and genomic information. Genotype information of 46,914 SNPs was available for 33,969 animals in the pedigree. When PPG used pedigree information only, BLUP converged after 2,420 iterations whereas the ssGBLUP evaluation needed over ten thousand iterations. When the PPG effects were solved accounting both the pedigree and the genomic information, the ssGBLUP model converged after 2,406 iterations. Also, with the latter model breeding values by ssGBLUP and BLUP became more consistent and genetic trends followed each other well. Models were validated using forward prediction of the young bulls. Reliabilities and variance inflation of predicted genomic breeding values (values for parent averages in brackets) for the 11 traits ranged 0.22–0.31 (0.10–0.27) and 0.81–0.95 (0.83–1.06), respectively. The ssGBLUP model gave always higher validation reliabilities than BLUP, but largest increases were for the cow fertility traits.     

喀斯特山区2个鲫鱼群体基于转铁蛋白的遗传多样性研究

为了解喀斯特山区2个不同鲫鱼群体在蛋白质水平的遗传多样性及其遗传差异,运用聚丙烯酰胺凝胶电泳方法对喀斯特山区2个群体鲫鱼的血清转铁蛋白电泳表型及多样性进行研究。结果表明:群体克隆多样性指数表现为草海鲫鱼(0.32)﹥红鲫(0.25,对照)﹥普安鲫鱼(0.13);3个鲫鱼群体的13个克隆由9个不同的等位基因产生,等位基因的频率分别为Tf~a0.144 9、Tf~b0.202 9、Tf~c0.036 2、Tf~d0.058 0、Tf~e0.007 2、Tf~f0.239 1、Tf~g0.014 5、Tf~h0.275 4、Tf~i0.029 0;普安鲫鱼与草海鲫鱼和红鲫无共享的基因型;普安鲫鱼与草海鲫鱼之间的遗传相似性指数较高(0.714 3),遗传距离较小(0.285 7)。总体来看,草海鲫鱼的克隆多样性水平较高,其转铁蛋白多样性程度较普安鲫鱼丰富;2个群体之间存在较近的亲缘关系,未达到遗传距离种的分化标准。     

人工合成小麦紫色胚芽鞘的遗传定位分析

为探明小麦花青素色素沉积的关键位点,以167份重组自交系群体为材料,利用已构建的高密度遗传图谱对来源于硬粒小麦(AABB)和节节麦亚种tauschii(DD)杂交后所得的人工合成小麦SHW-L1中控制紫色胚芽鞘的基因进行遗传定位。同时利用目标性状关联遗传区段对SHW-L1及其亲本进行基因型鉴定。结果表明:目标性状在重组自交系群体中表现为单基因遗传,且被定位于7D染色体,其关联遗传区段在异源六倍化过程中有遗传位点缺失。     

不同来源花生品种的ISSR分析及亲缘关系研究

利用13对ISSR引物对28个栽培种花生品种进行PCR扩增,研究这些品种的DNA多态性及其亲缘关系。结果表明,有7对引物检测到明显的多态性,从28个花生品种中扩增出90条带,其中多态性带达到79条,多态性比率为87.8%,平均每个引物可扩增出12.86条带,11.29条为多态性条带。品种间的遗传相似系数值在0.411~0.800之间,平均为0.620。在UPGMA聚类分析简单匹配系数值为0.57处,可把28个花生品种分成3个品种群。由此表明,这些不同来源的花生品种具有较高的DNA多态性,亲缘关系不同。     

结球甘蓝抽薹性遗传规律和QTL定位分析

以早抽薹‘S-1’与晚抽薹‘G-1’为亲本，构建F1、BC1、BC2和F2群体，采用植物数量性状主基因 + 多基因混合遗传模型分析法对结球甘蓝抽薹性状进行遗传分析，并采用SLAF-BSA方法对抽薹时间进行QTL定位分析。结果显示，结球甘蓝抽薹性状是由2对加性—显性—上位性主基因 + 加性—显性多基因遗传控制；主基因 + 多基因平均遗传率是93.41%。共检测到2个QTL，分别为2号染色体上的2.31 ~ 3.09 Mb和33.57 ~ 34.40 Mb，总长度为1.61 Mb。     

Relationship of Icelandic cattle with Northern and Western European cattle breeds,admixture and population structure

ABSTRACT

Icelandic cattle is believed to have been brought from Norway during the settlement of Iceland around AD 870-930. Previous research on genetic relationships has indicated that Icelandic cattle is most related to northern Nordic indigenous breeds. Using single nucleotide polymorphism genotype data from Icelandic cattle and 29 Northern and Western European cattle breeds, we studied relationships and admixture among these breeds, and assessed population structure in Icelandic cattle. Population structure analysis through principal component analysis, estimation of ancestry, and analysis of patterns of population splitting and mixing revealed that Icelandic cattle are most related to three Finncattle breeds (Eastern, Northern and Western Finncattle), and Swedish Mountain cattle. Icelandic cattle has very low levels of admixture. We observed very limited population structure in Icelandic cattle. The observed structure was due to variable sire contributions. Over 1000 years of almost complete isolation has made Icelandic cattle highly genetically distinct from other cattle breeds.     

胡萝卜根中主要类胡萝卜素含量相关QTL的精细定位

以白色的野生胡萝卜‘松滋野生’(Ws)和橘色的栽培胡萝卜品种‘Amsterdam’(Af)为亲本构建的回交重组自交系(BIL)为试材,基于低倍重测序技术开发SNP标记,构建了由1 976个Bin标记组成,包含29 435个SNP标记的遗传图谱。图谱总距离834.28 c M,平均图距0.42 c M。通过对胡萝卜肉质根中类胡萝卜素含量相关QTL分析,在连锁群LG04和LG08中检测到调控α–胡萝卜素、β–胡萝卜素、ζ–胡萝卜素、叶黄素、玉米黄质和总类胡萝卜素含量的主效QTL(M-QTL)2、2、3、2、2和2个,表型贡献率为11.47%~19.18%;另检测到调控α–胡萝卜素、β–胡萝卜素、ζ–胡萝卜素、玉米黄质和总类胡萝卜素含量的上位性QTL(E-QTL)1、1、2、1和1个,表型贡献率为2.50%~3.66%。在M-QTL显著区间内共检索到36个有功能注释的预测基因,其中Dck018297为ζ–胡萝卜素脱氢酶2基因,与调控β–胡萝卜素合成和总类胡萝卜素含量有关;Dck008006为乙烯响应因子2.2的同源基因,与调控α–胡萝卜素、ζ–胡萝卜素合成有关;Dck029898为转录因子b HLH135的同源基因,与调控玉米黄质合成有关。