The effects of temperature and aging of Drosophila males on the frequencies of XXY and XO progeny

Drosophila males of the constitution y/y⁺Y were aged for 10 days at 25° and 10° and then mated daily for 13 days at 25° to virgin yw (XX) females. The total frequencies of exceptional XXY and XO offspring to which the father contributed either (a) both an X and a Y chromosome, or (b) neither of them, were highly significantly more numbers in the 7th- and 8th-day broods of the 10° than the 25° pre-aged series. In all experiments the frequency of paternal XO exceptions was greatly in excess of that of XXY exceptions. The data on brood patterns suggest that the stages most sensitive to the production of paternal exceptions by pre-aging at 10° are those of the primary spermatocytes. The same stages are also sensitive to low temperature induction of temporarily low fertility.     

Characterization of the progeny of X-ray irradiated males from two Drosophila virilis strains differing in genetic instability.

Significant effects of X-ray treatment on the increase in the number of phenotypic variations, two visible mutations, and chromosome aberrations were found in the progeny of irradiated males from the D. virilis laboratory stock that is capable of hybrid dysgenesis syndrome induction. This effect is much more pronounced than in the progeny of irradiated males from strong wild-type strains studied. A correlation between genetic instability and chromosome radiosensitivity was outlined. The mechanism of this phenomenon and the possibilities of using the property of genome instability for the productive induction of gene and chromosome damage in radiation mutagenesis experiments are discussed.     

Origin of X/O progeny from crosses of sex-ratio trait males of Drosophila pseudoobscura

Males of Drosophila pseudoobscura carrying the sex-ratio chromosome (SR) were studied to determine the cause of X/O male progeny that they produce. It was found that among 3671 X/O progeny virtually all resulted from nullo-X sperm. The experiment also revealed a dramatic clustering of the frequency of X/O progeny among SR/Y males. This is interpreted to indicate that premeiotic events in the male germ line are the cause of nullo-X sperm.     

乳酸杆菌对实验性急性胰腺炎损伤的治疗价值

目的探讨乳酸杆菌对急性胰腺炎的治疗作用。方法采用家兔急性胰腺炎模型,其中实验组给予乳酸杆菌干预,检测实验组、对照组血清淀粉酶、血清钙和血糖3项指标。结果实验组血清淀粉酶水平低于对照组(P<0.01)。结论乳酸杆菌对实验性急性胰腺损伤有修复作用。     

肉桂优树子代测定初报

对福建省华安金山林场25年生肉桂人工林的70株初选优树的半同胞子代进行遗传测定,方差分析结果表明,家系间在树高、地径上差异显著,参试的优树子代平均树高、地径分别超过对照家系78.6%、91.5%。通过聚类分析,初步分出5个类群,其中Ⅰ、Ⅱ类中11个家系属早期速生类型,有待于进一步重点观测。     

Genetic evidence for fewer progeny and a higher percent males whenNasonia vitripennis oviposits in previously parasitized hosts

Genetically markedNasonia vitripennis females that oviposited second or third on aSarcophaga bullata pupa produced fewer progeny than those that were the first to oviposit on the host. The proportion of males in these progeny was also significantly increased (p.<0.001). Implications of these results on the evolution of hymenopterous parasites are discussed.     

Spontaneous and bleomycin-induced genomic alterations in the progeny of Drosophila treated males depends on the Msh2 status. DNA fingerprinting analysis

Deficiency in DNA mismatch repair (MMR) confers instability of simple repeated sequences and increases susceptibility to cancer. Some of the MMR genes are also implicated in other repair and cellular processes related to DNA damage response. Supposedly, lack of their function can lead to a global genomic instability, besides microsatellite instability (MSI). To study the spontaneous and induced genomic instability in germ cells, related to the Msh2 status, DNA alterations in the progeny of individual crosses of Drosophila deficient in one or two copies of the Msh2 gene, were analysed by the arbitrarily primed polymerase chain reaction (AP-PCR). The results indicate that the progeny of homozygous parents for the normal Msh2 allele (+/+) presents a significantly lower frequency of genomic alterations than those from heterozygous (+/-) or mutant homozygous (-/-) parents. In addition, the DNA damage transmitted to the progeny, after the adult parental males were exposed to bleomycin, indicates that whereas the induction of mutations related to MSI depends on the lack of the Msh2 function, the induction of other mutational events may require at least one functional Msh2 allele. Thus, the results obtained with heterozygous individuals may have special relevance for cancer development since they show that a disrupted Msh2 allele is enough to generate genomic instability in germ cells, increasing the genomic damage in the progeny of heterozygous individuals. This effect is enhanced by mutagenic stress, such as occurs after bleomycin exposure.     

Selection system efficiencies for computer simulated progeny test field designs in loblolly pine

Summary Six simulated progeny test field designs in combination with three within-family selection systems were tested on three loblolly pine (Pinus taeda L.) progeny test sites in southeastern Oklahoma and southwestern Arkansas, to compare genetic gains for the single trait, height. Residual deviations obtained by subtraction of family and plantation mean effects for each plantation were combined with simulated genetic effects with known family variance structure. The simulated genetic populations, arranged in the following progeny test field designs — large square or almost square plots, five- and ten-tree row plots, five-tree noncontiguous plots, two tree row plots, and single-tree plots — were superimposed on the residual data for each plantation. Within-family selection methods based on deviations from block means, deviations from neighborhood means and deviations from plot means were built into the model. Realized genetic gain attained by each design — selection system combination was compared with the genetic gain theoretically possible if selection accuracy were perfect, and with expected gain estimated using the general linear model. In general, average realized genetic gain compared well with expected gain. Differences between designs with large versus small plots were generally lower than expected, although the single-tree plot design always yielded highest realized gain. Realized gain was generally higher than expected when within-family selection was based on deviations from block or neighborhood means, but equal to or lower than expected when selection was based on deviations from plot means.     

The information value of a questionnaire test in an epidemiologic survey

To find out persons with decreased immune responsiveness in organized groups, the inquiry test has been proposed. The test has proved to be highly informative. Besides, the possibility of using this method for the characterization of the effectiveness of epidemic control measures has been shown.