Pregnancies from biopsied human preimplantation embryos sexed by Y-specific DNA amplification

Over 200 recessive X chromosome-linked diseases, typically affecting only hemizygous males, have been identified. In many of these, prenatal diagnosis is possible by chorion villus sampling (CVS) or amniocentesis, followed by cytogenetic, biochemical or molecular analysis of the cells recovered from the conceptus. In others, the only alternative is to determine the sex of the fetus. If the fetus is affected by the defect or is male, abortion can be offered. Diagnosis of genetic defects in preimplantation embryos would allow those unaffected to be identified and transferred to the uterus. Here we report the first established pregnancies using this procedure, in two couples known to be at risk of transmitting adrenoleukodystrophy and X-linked mental retardation. Two female embryos were transferred after in vitro fertilization (IVF), biopsy of a single cell at the six- to eight-cell stage, and sexing by DNA amplification of a Y chromosome-specific repeat sequence. Both women are confirmed as carrying normal female twins.     

Division of labor:different tasks for PRC1 and PRC2 in preimplantation embryos

Epigenetic regulation on gene expression is key to the decision and maintenance of cell fates during development.One of the old-est and the most explored epigen...     

卵巢运输条件对牦牛卵母细胞质量与胚胎体外发育的影响

卵巢的运输条件是影响卵母细胞的质量与胚胎发育的主要因素之一.为了找到牦牛卵巢的最佳运输温度,将采集的新鲜牦牛卵巢分别置于15-20℃、25-30℃、35-40℃的生理盐水中,1-2 h送回实验室,比较不同运输温度下的可利用COCs回收率、卵母细胞成熟率、孤雌激活与体外受精胚胎的体外发育.结果表明35-40℃运输卵巢能显著提高牦牛可利用COCs回收率(72.0％),但25-30℃组卵母细胞成熟率与其它组差异显著(78.9％);25-30℃组的卵母细胞进行孤雌激活与体外受精后,8细胞和囊胚形成率显著高于其它组(P＜0.05).由此推测:25-30℃为牦牛卵巢的最佳运输温度,能显著提高卵母细胞质量与胚胎体外发育能力.     

Combinational electroporation and transplantation approach to studying gene functions in avian embryos

Gene transfection is an indispensable approach for studying gene function since it provides important information on gain- and/or loss-of-function. Chick embryos are also extensively employed for studying bio- logical function since they are easily accessible and can be maintained alive after manipulation. The combination of both techniques presents a powerful approach to under- standing how genes regulate embryo development. Fur- thermore, combining these approaches with tissue transplant techniques make even more attractive for elu- cidate gene function. Electroporation, employing parallelly fashioned electrodes, has been widely used in chick embryos. However, experimenters have been frustrated by unsuccessfully transfection in some embryonic tissue of interest because the electrodes were improperly positioned.We presently demonstrated the different patterns of orga- nizing and positioning the electrodes, in combination with tissue transplantation, to efficiently and specifically trans- fect the chick embryonic head, trunk neural tube, heart tube, somites and neural crest cells with the GFP reporter gene.     

凸函数与超加函数的关系研究

应用积分理论，研究了在整数规划中具有重要应用的凸函数及其超加函数的关系。利用超加函数的有关结论，证明了任何过原点的凸函数必为超加函数，并得到了此类凸函数的若干推论。     

鱼类线粒体基因组研究进展

线粒体基因组(mitochondrial genome DNA,mtDNA)具有严格的母系遗传且能进行自我复制,并且在世代传递过程中不易发生重组、进化速率较快等优点.因此mtDNA广泛应用于系统进化、种群遗传、适应性进化等领域中.本文对鱼类mtDNA研究做了详细阐述,系统总结了近年来鱼类mtDNA结构与特征、线粒体的起源与演化、种群遗传、适应性进化、鱼类条形码物种识别等研究进展,以期对相关研究有一定参考价值.     

哈密翼龙及其3D胚胎化石研究

 翼龙是地球上第一类飞向天空也是唯一绝灭的飞行脊椎动物,人类对其产卵繁殖、生长发育和生活习性等方面的了解还十分有限。本文介绍了一件超过200枚哈密翼龙蛋、胚胎和骨骼化石三位一体保存的重要标本,包括16枚翼龙蛋含有三维立体的胚胎化石。针对这件全世界首次发现的3D翼龙胚胎,研究提出哈密翼龙具有相对早熟的胚胎发育模式,其后肢发育速度较前肢快,孵化之后只能走不能飞;胚胎发育期间牙齿尚未萌出,出生后还需要父母照料;从胚胎到亚成年都具有快速生长的骨骼结构;显示哈密翼龙具有群居的生活习性,白垩纪的湖泊风暴导致其集群死亡并快速埋藏。     

Mitochondrial DNA and human evolution

Mitochondrial DNAs from 147 people, drawn from five geographic populations have been analysed by restriction mapping. All these mitochondrial DNAs stem from one woman who is postulated to have lived about 200,000 years ago, probably in Africa. All the populations examined except the African population have multiple origins, implying that each area was colonised repeatedly.     

关于preinvex函数和pseudoinvex函数

本文讨论了可微的强invex函数和强pseudoinvex函数分别与其梯度的强不变单调和强不变伪单调的关系,得到了pseudoinvex函数在某些条件下可以等价prequasiinvex函数.证明了:若f关于向量值函数η是preinvex函数,且满足lipschitz条件,则y为f(x)的全局极小点等价于0∈(e)0f(y).     

丰鲤及其双亲线粒体DNA限制性酶切图谱的研究

采用密度梯度离心及RNase消化法制备并纯化了丰鲤(Fengcarp)、兴国红鲤(Xingguoredcarp)及散鳞镜鲤(Scatterscaledmirrorcarp)的肝脏线粒体DNA,用10种限制性内切酶HindIII、EcoRI、BamHI、XbaI、XhoI、PstI、BglII、SalI、BglI、PvuII进行了分析.丰鲤mtDNA相对分子质量约为9 88×106,大小约为16 49kb;兴国红鲤mtDNA相对分子质量约为9 89×106,大小约为16 50kb;散鳞镜鲤mtDNA相对分子质量约为9 87×106,大小为16 48kb.HindIII、EcoRI、BglI、BamHI、XbaI、XhoI、SalI、BglII、PstI及PvuII在丰鲤、兴国红鲤、散鳞镜鲤线粒体DNA分子上均分别有6、4、3、3、3、1、1、0、1和4个切点.根据单酶切及双酶切结果,构建了丰鲤、兴国红鲤、散鳞镜鲤mtDNA9种酶的限制性酶切图谱,结果表明丰鲤、兴国红鲤及散鳞镜鲤mtDNA间缺乏变异性.