Parentage determination in maize hybrids using the arbitrarily primed polymerase chain reaction (AP-PCR)

Summary Using a novel procedure based on the polymerase chain reaction, we have developed a rapid, efficient, and economical method for identifying plant genotypes. The arbitrarily primed polymerase chain reaction (AP-PCR) generates reproducible fingerprints from any organism, without the need for DNA sequence information. These fingerprints include DNA fragment polymorphisms that can be (1) used for varietal identification and parentage determination, (2) followed in segregating populations produced by crosses, (3) used as markers for the construction of genetic maps, and (4) used to generate dendograms of phylogenetic relationships, especially at the intraspecific level. AP-PCR requires only minute quantities of DNA (10–25 ng per reaction) and therefore can be used in situations in which DNA is limiting. We demonstrate the use of AP-PCR to identify inbred parents of hybrid maize plants in double-blind experiments.     

雄性普通黄颡鱼与所保护受精卵间的亲缘关系分析

父母通过保护自己的子代来确保其繁殖的成功率.在普通黄颡鱼(Pelteobagrus fulvidraco)中,雄性普通黄颡鱼具有筑巢产卵保护后代的习性,其所保护的子代与其是否有亲缘关系是有待探讨的问题.本文利用10对微卫星分子标记鉴定12窝普通黄颡鱼受精卵与护卵鱼之间的亲缘关系,并对子代的遗传多样性进行分析.在单亲鉴定中,累积非父排除概率为0.9986,平均父权相对机会(RCP)在99.989%-99.999%之间,每个子代在10个微卫星位点上的累积PI值在2006.73-604464.07之间.同时在亲权鉴定分析中,发现3窝卵子的等位基因来自2个母亲,说明雄性黄颡鱼可以和2条雌性黄颡鱼发生交配;在遗传多样性分析中,黄颡鱼子代的平均等位基因数为11.7, 无偏观测杂合度值(Ho)在0.2473-0.9866之间,多态信息含量(PIC)值0.7096-0.8993之间.通过亲权鉴定分析,可以确认看护受精卵的雄性普通黄颡鱼与受精卵间的亲子关系.     

Why do females care more than males?

Females tend to provide more parental care than males. Previous efforts to account for this have been confused because it is difficult to express the costs of care for males and females in the same currency. Here I propose a null model that does so, using the Fisherian constraint that total male and female reproduction must be equal. The model shows that, contrary to a number of recent analyses, lower probability of parentage for males does tend to make males less likely than females to provide care. It also shows how sexual selection stemming from premating asymmetries in investment promotes similar post-mating asymmetries.     

微卫星标记在不同壳色虾夷扇贝家系亲权鉴定的适用性

实验选取8 个多态性微卫星位点, 用于虾夷扇贝4 个不同壳色全同胞和半同胞家系160 个子代的亲权鉴定。在亲本未知和一亲本已知的情况下, 8 个微卫星位点累积排除概率分别为0.823 和0.961。鉴于亲权分析时子代的亲本在已知和未知情况下位点的累积排除概率不同, 实验采用了两种方法用于家系的亲权鉴定。方法1: 当子代的父母本情况未知时, 根据子代基因型数据, 通过CERVUS 2.0 软件计算子代所对应的候选亲本的LOD 值, 直接将候选亲本中具有最大的两个LOD 值的亲本确定为子代的父母本; 方法2: 在子代的亲本未知情况下, 视具有最大LOD 值的候选亲本为子代的第一候选亲本, 然后将该亲本视为已知, 通过CERVUS 2.0 软件重新计算每个侯选亲本的LOD 值, 再从中选择具有最大LOD 值的候选亲本作为该子代的第二候选亲本。结果表明, 采用方法2 得到的家系亲权鉴定成功率达到95%以上, 确定了微卫星标记在虾夷扇贝家系鉴定中的可行性。所检测的微卫星位点在子代中出现无效等位基因现象, 而无效等位基因存在会引起子代与亲本的错配。实验在家系鉴定时采用了无效等位基因存在(情况1)和缺失(情况2)两种子代基因型文件进行分析, 不同情况下同一方法家系鉴定成功率相差无几。这表明了基于多个微卫星位点计算候选亲本LOD 值大小寻找子代真实父母本可以降低由无效等位基因引起的错配的几率。研究表明了微卫星标记适合于不同壳色虾夷扇贝家系亲权鉴定工作。       

sh-2甜玉米F2籽粒营养品质遗传特点、杂种优势及其亲子回归关系分析

研究了25个sh-2甜玉米自交系及其组配的15个sh-2型F_2籽粒的5个品质性状的遗传特点、杂种优势、亲子回归关系．结果表明,亲本间,除籽粒还原糖含量外,可溶性总糖、蔗糖、淀粉、可溶性蛋白含量是否存在显著差异,对F_2籽粒品质有明显影响．F_2籽粒可溶性总糖、还原糖、淀粉、可溶性蛋白含量近低亲遗传,而蔗糖含量近高亲遗传．杂种F_2籽粒可溶性总糖、淀粉、可溶性蛋白含量普遍介于双亲之间,杂种优势不强;还原糖含量普遍表现为低亲,没有超亲优势;蔗糖含量以超亲为主,有明显杂种优势．亲本对F_2杂交籽粒可溶性总糖、还原糖、蔗糖、淀粉、可溶性蛋白含量均表现为正效应;除还原糖品质外,其他品质性状受父本的影响较大．研究表明,了解sh-2甜玉米亲本营养品质性状,能很好的预测其F_2籽粒营养品质性状,使育种更有目的性．     

Dispersal and habitat cuing of Eurasian red squirrels in fragmented habitats

Animal dispersal and subsequent settlement is a key process in the life history of many organisms, when individuals use demographic and environmental cues to target post-dispersal habitats where fitness will be highest. To investigate the hypothesis that environmental disturbance (habitat fragmentation) may alter these cues, we compared dispersal patterns of 60 red squirrels (Sciurus vulgaris) in three study sites that differ in habitat composition and fragmentation. We determined dispersal distances, pre- and post-dispersal habitat types and survival using a combination of capture–mark–recapture, radio-tracking and genetic parentage assignment. Most (75%) squirrels emigrated from the natal home range with mean dispersal distance of 1,014 ± 925 m (range 51–4,118 m). There were no sex-related differences in dispersal patterns and no differences in average dispersal distance, and the proportion of dispersers did not differ between sites. In one of the sites, dispersers settled in patches where density was lower than in the natal patch. In the least fragmented site, 90% of animals settled in the natal habitat type (habitat cuing) against 44–54% in the more strongly fragmented sites. Overall, more squirrels settled in the natal habitat type than expected based on habitat availability, but this was mainly due to individuals remaining within the natal wood. In the highly fragmented landscape, habitat cuing among emigrants did not occur more frequently than expected. We concluded that increased habitat fragmentation seemed to reduce reliable cues for habitat choice, but that dispersing squirrels settled in patches with lower densities of same-sex animals than at the natal home range or patch, independent of degree of fragmentation.     

DNA-based monitoring of two newly founded Scandinavian wolverine populations

The wolverine is an endangered carnivore that in northwestern Europe is restricted to the mountain range along the border between Sweden and Norway. The Scandinavian wolverine population experienced a severe decline in numbers due to human persecution during the 20th century, although with legislative protection the population has recently implied that the population slowly has started to recover (current population size estimate of 800 individuals). In the mid 1990s, wolverines appeared in two new and isolated areas east of the mountain range, in the forest landscape close to the Gulf of Bothnia. Using non-invasive, DNA-based monitoring, we show here that these new subpopulations were likely founded by as few as 2 and 2–4 individuals, respectively, and that little, if any, genetic contact with the main population since colonisation has been established. A high degree of genetic similarity among individuals in the two areas indicates inbreeding. We estimate the minimum number of wolverines known to be alive in these areas during the period of 2001–2005 to 5 and 17, respectively, with one subpopulation showing decreasing (currently 2) numbers and the other increasing (10). For the somewhat larger population, we infer a tentative pedigree from relatedness values and parentage tests, which indicates the occurrence of brother–sister matings. This study illustrates the usefulness of non-invasive monitoring in the management of endangered carnivore populations.     

Parentage analyses of freshwater goby Rhinogobius sp. OR using microsatellite DNA markers and egg developmental stages of eggs in the nest

Parentage analyses of the paternally caring goby Rhinogobius sp. OR were performed using microsatellite DNA markers and examination of developmental stages of eggs collected from five nests with parental males in the wild. Four of five nests had egg masses with eggs at the same developmental stages from single females. In one nest, the egg mass with eggs at three different developmental stages originated from four females, and eggs of whole developmental stages were observed within the egg mass of each female. This observation suggests that in this goby embryonic stage is an inaccurate indicator of the number of mates.     

Evidence of genetic and environmental influences on meristic variation in the rainbow trout,Salmo gairdneri Richardson

Synopsis An investigation of the effect of parentage and temperature on the expression of selected meristic characters of rainbow trout, Salmo gairdneri, reveals statistical differences in the number of vertebrae, dorsal fin rays and anal fin rays among test batches of progeny of different parentage. Batches of fertilized ova of the same stock or parentage, when incubated at 9.5 °C and 14.8 °C, produced lower mean dorsal and anal fin ray counts and a higher mean pectoral fin ray count at the higher temperature. Incubation temperature had no significant effect on the number of vertebrae.Significant statistical differences occurring in various characters among groups of rainbow trout of different parental origin provide convincing evidence of genetic inputs into meristic expression. However, the existence of both environmental and genetic inputs into meristic expression in rainbow trout necessitates further investigation before the meaning of observed meristic plasticity in rainbow trout can be resolved.     

人体基因组D14S13位点限制性片段长度多态性的研究

应用pCE1.2探针,分析了296个无关个体基因组D14S13位点Haelll酶解的限制性片段长度多态性（RFLP）,进行了等位基因频率的分布统计,发现至少含有66个等位基因,位点杂合性大于93％,在对8个家系93名相关个体的分析中,没有发现突变发生,此RFLP分析方法已初步应用于法医学的个人识别和亲权鉴定中,并对准确度进行了计算。》