多囊卵巢综合症与心血管疾病相关性的探讨

多囊卵巢综合症(Polycystic ovary syndfome,PCOS)是一种育龄期妇女常见病,临床上常伴有月经稀少、不孕、多毛和肥胖等症状,双侧卵巢呈囊性增大,女性内分泌出现紊乱,PCOS中有50%妇女表现为肥胖,尽管多数妇女以不孕和月经异常就诊,但有研究表明PCOS患者的远期并发症如心血管疾病的发生率远远高于正常人群。本文主要探讨了PCOS与心血管疾病的相关性。     

Genome-Wide Survey of Hybrid Incompatibility Factors by the Introgression of Marked Segments of Drosophila Mauritiana Chromosomes into Drosophila Simulans

In hybrids between Drosophila simulans and D. mauritiana, males are sterile and females are fertile, in compliance with HALDANE's rule. The genetic basis of this phenomenon was investigated by introgression of segments of the mauritiana genome into a simulans background. A total of 87 positions throughout the mauritiana genome were marked with P-element insertions and replicate introgressions were made by repeated backcrossing to simulans for 15 generations. The fraction of hemizgyous X chromosomal introgressions that are male sterile is ~50% greater than the fraction of homozygous autosomal segments. This result suggests that male sterility factors have evolved at a higher rate on the X, but chromosomal differences in segment length cannot be ruled out. The fraction of homozygous autosomal introgressions that are male sterile is several times greater than the fraction that are either female sterile or inviable. This observation strongly indicates that male sterility factors have evolved more rapidly than either female sterility or inviability factors. These results, combined with previous work on these and other species, suggest that HALDANE's rule has at least two causes: recessivity of incompatibility factors and differential accumulation of sterility factors affecting males and females.     

The immotile-cilia syndrome: a microtubule-associated defect

The immotile-cilia syndrome is a congenital disorder characterized by all the cilia in the body being either immotile or showing an abnormal and inefficient beating pattern. Most symptoms come from the ciliated airways (nose, paranasal sinuses, and bronchs) and from the middle ear. Two further symptoms are situs inversus and male sterility. Situs inversus occurs in 50% of the cases and this subgroup is termed the Kartagener's syndrome; it might be due to an inability of the embryonic cilia to shift the heart to the left side and situs laterality seems to be a random process in the immotile-cilia syndrome. Male sterility is caused by the spermatozoa being unable to swim progressively; the sperm tail has the same structure as a cilium. In a few cases only the sperm tail or only the cilia of the body are affected. Female patients have a decreased fertility; most are involuntarily childless. The immotile-cilia syndrome is a heterogeneous disorder in that one out of many different genes may be involved. The different subtypes can be distinguished by an electron microscopic examination which will show defects in either one of a number of the ciliary components.     

inv(9)(p24q13) in three sterile brothers

Only nine non-polymorphic constitutional pericentric inversions of chromosome 9 have been described. We report on a familial inv(9)(p24q13) associated with sterility in three brothers. The mother's chromosomes were normal in blood lymphocytes (n=130); the father was already deceased and his karyotype unknown. However, the presence of any of the maternal chromosomes 9 (as assessed by C-banding) in her carrier children is inconsistent with the assumption of maternal mosaicism. Two single sisters were also carriers. The same rearranged chromosome 9 in the three sterile brothers can hardly be regarded as a fortuitous association, especially when the breakpoints are almost identical to those of the sole inversion previously found in an azoospermic male. If their father was a carrier, the observed sterility may be the result of 'chromosome anticipation', a phenomenon already invoked for certain familial chromosomal rearrangements.     

Hybrid Dysgenesis in DROSOPHILA MELANOGASTER: The Biology of Female and Male Sterility

High levels of female and male sterility were observed among the hybrids from one of the two reciprocal crosses between a wild strain of D. melanogaster known as pi2 and laboratory strains. The sterility, which is part of a common syndrome called hybrid dysgenesis, was found to be associated with the rudimentary condition of one or both of the ovaries or testes. All other tissues, including those of the reproductive system were normal, as were longevity and mating behavior. The morphological details of the sterility closely mimic the agametic condition occurring when germ cells are destroyed by irradiation or by the maternal-effect mutation, grandchildless. We suggest that sterility in hybrid dysgenesis is also caused by failure in the early development of germ cells. There is a thermo-sensitive period beginning at approximately the time of initiation of mitosis among primordial germ cells a few hours before the egg hatches and ending during the early larval stages. Our results suggest that hybrid dysgenesis, which also includes male recombination, mutation and other traits, may be limited to the germ line, and that each of the primordial germ cells develops, or fails to develop, independently of the others. This hypothesis is consistent with the observed frequencies of unilateral and bilateral sterility, with the shape of the thermosensitivity curves and with the fact that males are less often sterile than females. The features of this intraspecific hybrid sterility are found to resemble those seen in some interspecific Drosophila hybrids, especially those from the cross D. melanogaster X D. simulans.     

Inna Golubovskaya: the life of a geneticist studying meiosis

Maize, with its excellent forward genetics and male sterility screens, was used to identify >50 meiotic mutants representing at least 35 genes that affect key prophase processes such as pairing, synapsis, and homologous recombination. Most of these mutants were found by Inna Golubovskaya during the course of her remarkable career as a cytogeneticist. In addition to undertaking general cytological surveys to classify mutant phenotypes, Golubovskaya focused her efforts on characterizing several key regulatory mutants: ameiotic1 (am1), required to establish the meiotic cell cycle in maize; absence of first division (afd1), required for proper prophase chromosome morphology and for meiotic sister-chromatid cohesion leading to a reductive chromosome segregation at the first meiotic division; and plural abnormalities of meiosis (pam1), required for the clustering of telomeres on the nuclear envelope needed for pairing and synapsis. Her dramatic childhood in Leningrad during its siege in World War II, her fortuitous education in genetics at Leningrad State University, her continued research at the forward-looking Institute of Cytology and Genetics of the USSR Academy of Science Siberian branch, her plight at the fall of the Soviet Union, and her work in America helped engender a unique and valuable plant geneticist. Inna Golubovskaya related this personal history to the authors in conversation.     

Population genetics of sexually antagonistic mitochondrial mutants under inbreeding

In random mating populations, the fate of mitochondrial mutations with sexually antagonistic effects in males and females is based solely on their effects in females. Therefore, mitochondrial mutations that are beneficial for females but deleterious for males will be fixed in a deterministic model. Why then are males not less fertile? One among many several explanations is that inbreeding limits the ability of mutants to spread since the fitness of a mother is now linked to her son's fertility. We model this situation analytically and determine conditions under which such sexually antagonistic mitochondrial mutants can spread and fix in a population. We also provide alternative hypotheses for the lack of observed male sterility in natural populations.     

Subfamily‐dependent alternative reproductive strategies in worker honeybees

Functional worker sterility is the defining feature of insect societies. Yet, workers are sometimes found reproducing in their own or foreign colonies. The proximate mechanisms underlying these alternative reproductive phenotypes are keys to understanding how reproductive altruism and selfishness are balanced in eusocial insects. In this study, we show that in honeybee (Apis mellifera) colonies, the social environment of a worker, that is, the presence and relatedness of the queens in a worker's natal colony and in surrounding colonies, significantly influences her fertility and drifting behaviour. Furthermore, subfamilies vary in the frequency of worker ovarian activation, propensity to drift and the kind of host colony that is targeted for reproductive parasitism. Our results show that there is an interplay between a worker's subfamily, reproductive state and social environment that substantially affects her reproductive phenotype. Our study further indicates that honeybee populations show substantial genetic variance for worker reproductive strategies, suggesting that no one strategy is optimal under all the circumstances that a typical worker may encounter.     

水稻亚种间杂种是否存在雌性不育？

水稻亚种间杂种不育性是一种普遍现象,但其遗传基础复杂。目前在亚种间杂种不育遗传上,不同研究的结论不尽一致,即使对亚种间杂种不育性主要表现为雄性不育还是雌性不育也存在争论。本对证明水稻亚种间杂种存在和不存在雌性不育的研究进行了综述与分析。从中可以看出无论是认为水稻亚种间杂种不育性表现为雄性不育还是雌性不育的结论都有一定的片面性,尤其是Sano证明基因座S－5不存在的研究存在较大的缺陷。因此,水稻亚种间杂种雌雄配子败育对小穗育性影响的大小有待进一步研究。     

The evolution of queen control over worker reproduction in the social Hymenoptera

A trademark of eusocial insect species is reproductive division of labor, in which workers forego their own reproduction while the queen produces almost all offspring. The presence of the queen is key for maintaining social harmony, but the specific role of the queen in the evolution of eusociality remains unclear. A long‐discussed scenario is that a queen either behaviorally or chemically sterilizes her workers. However, the demographic and ecological conditions that enable such manipulation are still debated. We study a simple model of evolutionary dynamics based on haplodiploid genetics. Our model is set in the commonly observed case where workers have lost the ability to lay female (diploid) eggs by mating, but retain the ability to lay male (haploid) eggs. We consider a mutation that acts in a queen, causing her to control the reproductive behavior of her workers. Our mathematical analysis yields precise conditions for the evolutionary emergence and stability of queen‐induced worker sterility. These conditions do not depend on the queen's mating frequency. We find that queen control is always established if it increases colony reproductive efficiency, but can evolve even if it decreases colony efficiency. We further derive the conditions under which queen control is evolutionarily stable against invasion by mutant workers who have recovered the ability to lay male eggs.     

Mohr-Majewski syndrome (orofaciodigital syndrome type IV) in five sibs.

We present a girl and autopsy finding of her sister with Mohr-Majewski syndrome (Orofaciodigital syndrome type IV). The parents were first cousins and their two sons died of similar findings. The only healthy child of the family was mildly effected from this syndrome who had cleft palate. These features show the heterogenity of the syndrome.     

Down's syndrome in the male. Reproductive pathology and meiotic studies

Studies on testicular histology and meiosis were carried out by the use of light and electron microscopy in an 18-year-old Down's syndrome male in an attempt to follow the fate of the extra chromosome 21 and to evaluate the effects of this condition on spermatogenesis and the reproductive functions. The histological changes in the testes corresponded to spermatogenic arrest. Electron microscopic whole-mount spreadings of meiotic cells in the pachytene stage showed that in most nuclei an extra chromosome 21 was not detectable. Only in a small number of nuclei, univalents or trivalents with segmental pairing structures of an extra chromosome could be discovered. In contrast, the great majority of (C-banded) diakinesis figures showed the presence of a supernumerary G (no. 21) chromosome. The absence of a traceable extra chromosome 21 in most pachytene cells is explained by the assumption that it is intimately connected with and hidden in the sex vesicle, whose complex structure does not allow the identification of single elements. Strong support for this assumption is seen (a) in the general tendency of narrow spatial association of unpaired segments with the XY complex and (b) in close structural similarities occurring between univalents or nonsynapsed segments of trivalents and the nonpaired segments of the sex chromosomes. It is suggested that the association or connection of an extra chromosome with the XY complex during pachytene interferes with the phenomenon of X inactivation. In animal systems such abnormal interference is related with spermatogenic breakdown and, in a general way, with male hybrid type sterility. So far, the range of sterility vs. fertility in cases of male Down's syndrome is not yet fully clear, but it appears that impairment of fertility, and sterility are most frequent. If so, it is proposed that the effect of the trisomy 21 condition on spermatogenesis (and fertility) is a consequence of the behavior of the extra chromosome in the meiotic prophase.     

雄性不育在作物杂种优势中的应用途径分析

雄性不育是植物雄性细胞或生殖器官丧失生理机能的现象,该现象的利用大大提高了杂交种生产的效率。植物雄性不育包含细胞质雄性不育、不受环境影响的核雄性不育、光温敏型雄性不育及化学诱导的雄性不育。这些不育类型也已经被以三系或二系的方式应用于很多作物的杂交种生产中。综述了雄性不育各个途径的研究进展及其在作物杂种优势中的应用。     

Female sterility in hybrids between Anopheles gambiae and A. arabiensis, and the causes of Haldane's rule

Although F1 female hybrids between Anopheles gambiae and A. arabiensis are fully fertile, sterility is present in backcross females. Here we report the results of a study into the genetic basis of backcross female sterility. Using 23 markers, we performed quantitative trait loci (QTL) mapping analyses to identify chromosomal regions involved in hybrid female sterility. We found that female sterility in backcrosses in both directions is primarily caused by interspecific interactions between a heterozygous X chromosome and recessive autosomal factors. In addition, our data provide support for two theories implicated in Haldane's rule in a single taxon. A comparison with data from a previous study shows that male hybrid sterility QTL are present in higher numbers than female hybrid sterility QTL. Furthermore, autosomal female sterility factors tend to be recessive, supporting the dominance theory for female sterility. Finally, our data indicate a very large effect of the X chromosome from both species on hybrid female sterility, despite the fact that the X chromosome represents less than 9% of the genome. However, this could be the result of a lack of introgression of the X chromosome between A. gambiae and A. arabiensis, rather than a faster evolution of sterility factors on the X chromosome.     

Genetics of Male Sterility in Gynodioecious Plantago Coronopus. II. Nuclear Genetic Variation

Inheritance of male sterility was studied in the gynodioecious species Plantago coronopus using five plants and their descendants from an area of ~50 m(2) from each of four locations. In each location, crosses between these five plants yielded the entire array of possible sex phenotypes. Both nuclear and cytoplasmic genes were involved. Emphasis is placed on the nuclear (restorer) genetics of two cytoplasmic types. For both types, multiple interacting nuclear genes were demonstrated. These genes carried either dominant or recessive restorer alleles. The exact number of genes involved could not be determined, because different genetic models could be proposed for each location and no common genetic solution could be given. At least five genes, three with dominant and two with recessive restorer allele action, were involved with both cytoplasmic types. Segregation patterns of partially male sterile plants suggested that they are due to incomplete dominance at restorer loci. Restorer genes interact in different ways. In most instances models with independent restorer gene action were sufficient to explain the crossing results. However, for one case we propose a model with epistatic restorer gene action. There was a consistent difference in the segregation of male sterility between plants from the two cytoplasmic types. Hermaphrodites of cytoplasmic type 2 hardly segregated male steriles, in contrast to plants with cytoplasmic type 1.     

The Fertility of Melanesian Girls, Laboratory Mice, and Prostitutes: A Comment on the "Bruce Effect"

Greenfield has recently proposed that low fertility in both prostitutes and unmarried Trobriand girls may be explained by the "Bruce effect": the inhibition of pregnancy in female mice that have had intercourse with different males within a short period. An examination of Malinowski's data indicates that a Trobriand girl usually had intercourse with only one man over a fairly long period and her sex life was not at all comparable to that of a prostitute or one of Bruce's mice. Low fertility in unmarried girls has been well documented for several Melanesian societies that differ notably in the behavior permitted to girls. The existence of so-called adolescent sterility still seems to be the best explanation to cover all of these cases. [fertility, sexual behavior, Melanesia]     

Life threatening sickle chest syndrome treated with extracorporeal membrane oxygenation.

A young West Indian woman with established sickle cell disease developed a severe episode of sickle chest syndrome. Conventional treatment including exchange transfusions and mechanical ventilation was to no avail, and an infusion of epoprostenol also failed to halt her worsening condition. When her arterial oxygen tension (PaO2) had fallen to 6.5 kPa (49 mm Hg) extracorporeal membrane oxygenation was instituted. Within two days her PaO2 was greatly improved (maximum 11.6 kPa; 87 mmHg), and by the sixth day pulmonary vascular resistance was reduced and angiography showed reperfusion of many vessels. The patient recovered and six months later showed a transfer factor close to the predicted range and normal spirometric values. Extracorporeal membrane oxygenation should be considered for severe sickle chest syndrome when conventional methods of artificial ventilation fail.     

Fertility Genes in Natural Populations of DROSOPHILA MELANOGASTER. I. Frequency, Allelism and Persistence of Sterility Genes

Three or four percent of the wild flies in natural populations of D. melanogaster have been found to be sterile. An analysis of sterility associated with the second chromosome revealed a much lower frequency of genetically sterile flies. The accumulation of sterility genes in a cage population was proportional to that of lethal genes, as were their equilibrium frequencies in several natural populations. Many sterile chromosomes were associated with low viability due to pleiotropic effects. The number of chromosomes leading to sterility in both sexes was larger than the expectation based on random combination of male and female sterility genes. This suggests that there is some linkage disequilibrium between male and female sterility genes, as well as a pleiotropic effect of single sterility genes. Some sterility genes were maintained in natural and cage populations, and the patterns of persistence of the sterility genes were very similar to those of lethal genes.     

Ring chromosome 21 in healthy persons: different consequencies in females and in males

Summary A stable ring chromosome 21 was found in an azoospermic man with an otherwise normal phenotype. Meiotic studies in another known azoospermic male with r(21) had indicated that breakdown of spermatogenesis resulted from pairing failure of chromosome 21, followed by degenerative changes in the chromosomes, before the cells had completed the first meiotic division. While primary sterility was a constant feature in the three adult males, eight healthy females with r(21) were fertile. However, they were at risk for Down syndrome and spontaneous abortions.