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PubMed1989

Ovariectomy attenuates aggression by female rats cohabiting with sexually active sterile males.

Female rats were individually housed with a single castrated male with a testosterone implant that maintained sexual and aggressive behavior. At weekly intervals, the resident male was removed and an unfamiliar female intruder was introduced into the colony. Attacks, bites, on-top, and piloerection of the resident female toward the intruder were scored. Females whose level of aggression toward the intruder was substantial and stable were either ovariectomized or sham-ovariectomized. Aggression tests resumed 1 week postoperatively and continued for an additional 3 weeks. The results confirm that female cohabiting with a sterile male become aggressive. They also demonstrate that ovariectomy greatly attenuates but does not entirely abolish aggression toward an unfamiliar female intruder. The results appear to contribute to a growing body of evidence suggesting that the biological substrate and behavioral form of aggression by females housed with males (including that following parturition) is a hormone-dependent aggression which parallels testosterone-dependent social aggression of males housed with females.

Aggression↗
PubMed1997

Leilani Muir versus the philosopher king: eugenics on trial in Alberta.

The Province of Alberta in Canada was the only jurisdiction in the British Empire where a eugenic sterilization law was passed (in 1928) and vigorously implemented. The pace of sterilization orders accelerated during the Nazi era and remained high after World War II, terminating only in 1972 when the Sexual Sterilization Act was repealed. The Alberta Eugenics Board operated away from public and legislative scrutiny, and many things done in the name of eugenics were clearly illegal. Eugenics was put on trial in Alberta in 1995 and a judge of the Court of Queen's Bench ruled in 1996 that the government had wrongly sterilized Leilani Muir. After hearing evidence about the history of the eugenics movement, the origins of Alberta's Sexual Sterilization Act, the operation of the Eugenics Board, and details of Muir's life, Madam Justice Joanne B. Veit found that 'the damage inflicted by the operation was catastrophic', the 'wrongful stigmatization of Ms. Muir as a moron ... has humiliated Ms. Muir every day of her life', and 'the circumstances of Ms. Muir's sterilization were so high-handed and so contemptuous of the statutory authority to effect sterilization, and were undertaken in an atmosphere that so little respected Ms. Muir's human dignity that the community's, and the court's, sense of decency is offended'. Veit awarded Muir damages of $740,780 CAD and legal costs of $230,000 CAD. The order for Muir's sterilization was signed by John M. MacEachran, founder of the Department of Philosophy and Psychology at the University of Alberta and chairman of the Eugenics Board from 1929 to 1965. An exponent of Platonic idealism, MacEachran believed sterilization of children with a low IQ test score was a means of 'raising and safeguarding the purity of the race'. However, the Alberta Sterilization Act was passed and implemented with cavalier disregard for the principles of genetics as well as the rights of children.

Adult↗
PubMedDate not supplied

The sexual nature of the eukaryote genome.

This paper supports a previous conjecture that the sexual cycle of eukaryotes arose from the infection of cells by genome parasites. The finding are as follows. (1) In prokaryotes, conjugative plasmids ensure their own spread by directing partial cell fusion. (2) Conjugative plasmids permit gene transfer between prokaryotes and eukaryotes, and can be integrated into the eukaryote genome. (3) Genes can be transferred between unrelated eukaryotes, and between different genomes within eukaryotic cells. (4) Elements such as transposons and retroviruses evolve as parasites of the eukaryote sexual system. (5) The mating-type genes of bipolar fungi are idiomorphic: alternative genes directing sexual specificity are dissimilar and non-homologous. It is argued that they arose as parasitic elements directing cell fusion, which have become integrated into the genome. (6) Mating-type idiomorphs in different taxa may be dissimilar, reflecting the independent acquisition of different infectious elements by different eukaryote lineages. (7) Sexual competence is rapidly lost through mutation accumulation or antagonistic pleiotropy during vegetative proliferation, so that many lineages are sexually sterile. (8) In multipolar systems, novel mating-type alleles arising by mutation spread in a parasite-like manner by virtue of their access to lineages which have become sexually sterile. (9) It is suggested that centromeres arise as devices to enable low copy number plasmids to persist. (10) Crossing over is favored if it enables the genes that direct it to unlink themselves from inferior genomes, or from the consequences of their own transposition.(ABSTRACT TRUNCATED AT 250 WORDS)

DNA Transposable Elements↗
PubMed1995

Sexually dimorphic sterility phenotypes in Hoxa10-deficient mice.

The Abdominal B (AbdB) genes constitute a distinct subfamily of homeobox genes that exhibit posterior domains of expression, including the genital imaginal disc in Drosophila and the developing urogenital system in vertebrates. We have mutated the AbdB gene Hoxa10 in mice. We report here that homozygotes are fully viable and show an anterior homeotic transformation of lumbar vertebrae. All male homozygotes manifest bilateral cryptorchidism resulting in severe defects in spermatogenesis and increasing sterility with age. Female homozygotes ovulate normally, but about 80% are sterile because of death of embryos between days 2.5 and 3.5 post coitum. This coincides spatially and temporally with expression of maternal Hoxa10 in distal oviductal and uterine epithelium. These results indicate a role for AbdB Hox genes in male and female fertility and suggest that maternal Hoxa10 is required to regulate the expression of a factor that affects the viability of preimplantation embryos.

Animals↗
PubMed1993

Infertility, infection, and iatrogenesis in Egypt: the anthropological epidemiology of blocked tubes.

In this article, we integrate medical anthropological and analytical epidemiological methods, forms of data analysis, and interpretive insights to examine the culture-specific behavioral factors that place poor, urban Egyptian women at risk of tubal-factor infertility (TFI). Such risk factors include biomedically and ethnomedically produced iatrogenesis, including the consequences of the practice of female circumcision, and male sexual behavior leading to sterilizing sexually transmitted diseases (STDs) in their female sexual partners. We examine the socio-cultural and political-economic context in which infertility-producing behavioral risk factors are maintained, and we explore the ways in which these risk factors are perceived by biomedically trained Egyptian gynecologists.

Adolescent↗
PubMed1996

Contraceptive use and attitudes in Italy 1993.

Surveys conducted between 1979 and 1991 indicated that contraceptive practice in Italy underwent rapid changes over that period. In order to assess current contraceptive use and attitudes, a survey was conducted among a random sample of 2000 Italian women aged 15-45 years. Replies were received from 1542 women (77.1%). Of the self-defined non-sterile, sexually active women who wished to avoid pregnancy, 30.3% were using oral contraceptives, 8.1% an intrauterine device, and 1.1% sterilization, while 29.6% were using traditional methods, principally coitus interruptus. In reply to questions about the relative advantages and disadvantages of various contraceptive methods, women expressed worries with respect to the safety of oral contraceptives, intrauterine devices and sterilization. Relatively high percentages of women answered 'do not know' with respect to the various aspects of intrauterine devices, periodic abstinence and sterilization that were investigated. In view of the findings of previous studies, the current data obtained suggested that traditional methods are being gradually displaced by modern methods in Italy. Nevertheless, the use of traditional contraceptive is widespread, the same probably being true of inconsistent use of condoms. Furthermore, lack of information on the contraceptive options available seems to be a central issue in Italy.

Adolescent↗
PubMed1996

"Democracy was never intended for degenerates": Alberta's flirtation with eugenics comes back to haunt it.

An Alberta woman recently won a lawsuit against the government of Alberta for wrongful sterilization that took place when she was a 14-year-old ward at the Provincial Training School for Mental Defectives. It was the first time the province has been held accountable for actions taken under the Sexual Sterilization Act, a 1927 law that promoted the theory of eugenics and led to the sterilization of more than 2800 people. It has since been repealed. A physician who served on the province's Eugenics Board said the decisions were based on the best scientific advice and medical techniques available at the time. Today, she added, eugenics is being practised in a different way through prenatal diagnosis and therapeutic abortion.

Alberta↗
PubMed1984

Laparoscopic sterilization in a free-standing clinic: a report of 1,092 cases.

The five-year experience of 1,092 laparoscopic tubal sterilizations performed in a free-standing clinic in the U.S. with no anesthesiologist under local anesthesia is reviewed. The current technique of the Hasson "open" method and bipolar cauterization is felt to minimize major mishaps and is acceptably comfortable to the patient.

Adolescent↗
PubMed2004

Evolutionary vestigialization of sex in a clonal plant: selection versus neutral mutation in geographically peripheral populations.

The loss of traits that no longer contribute to fitness is widespread; however, the causative evolutionary mechanisms are poorly understood. Vestigialization could proceed through the fixation of selectively neutral degenerative mutations via genetic drift. Alternatively, selection may facilitate vestigialization if trait loss results in enhanced fitness. We tested these hypotheses using Decodon verticillatus, a clonal plant in which sexual sterility has arisen repeatedly in populations across the northern geographical range limit. We compared growth and survival of replicated genotypes from 7 sexually fertile and 18 sterile populations, over 3 years in a common environment. Survival of sterile genotypes was 53% greater than for fertile genotypes, but there was no difference in biomass accumulation. Almost all mortality, and hence increased performance of sterile genotypes, occurred during simulated overwinter dormancy. These observations suggest that selection has facilitated the vestigialization of sex, and thus do not support the neutral mutation hypothesis. The selective mechanism probably involves the relaxation of a genetic trade-off between sexual reproduction and survival: alleles that increase vegetative performance at the expense of sexual fertility are selected in geographically peripheral populations where sexual reproduction is suppressed by adverse environmental conditions.

Analysis of Variance↗
PubMed2005

Experimental sexual selection in Chlamydomonas.

Sexual and asexual lines of the unicellular chlorophyte Chlamydomonas reinhardtii were propagated for about 100 sexual cycles and 1000 vegetative cycles in contrasted environments, liquid and solid growth media, in order to generate divergent natural and sexual selection. Sexual lines were transferred by many zygotes or by a single zygote in each sexual generation. By the end of the experiment zygote production was in the order sexual mass-transfer>sexual single-zygote>asexual>ancestor. The direct response to sexual selection was large, with zygote production increasing by about two orders of magnitude, mainly because mating had become spontaneous instead of being invoked by nitrogen starvation. Asexual lines became sexually sterilized by the fixation of a single mating type. Sexual selection caused a radical shift in the gender system, with homothallism spreading to high frequency in all sexual lines of this normally heterothallic species. This may have been caused by the transposition of a mating-type gene to an autosome. No substantial degree of environment-specific mating evolved, however, and thus no sexual isolation indicative of incipient speciation. It is possible that selection experiments of this kind are unlikely to induce sexual isolation because mating-type genes evolve in a saltatory fashion.

Animals↗
PubMed1951

STERILIZATION.

Explore the source record for details and available documents.

Sexual Behavior↗
PubMed2003

Population genetic consequences of extreme variation in sexual and clonal reproduction in an aquatic plant.

Most plants combine sexual reproduction with asexual clonal reproduction in varying degrees, yet the genetic consequences of reproductive variation remain poorly understood. The aquatic plant Butomus umbellatus exhibits striking reproductive variation related to ploidy. Diploids produce abundant viable seed whereas triploids are sexually sterile. Diploids also produce hundreds of tiny clonal bulbils, whereas triploids exhibit only limited clonal multiplication through rhizome fragmentation. We investigated whether this marked difference in reproductive strategy influences the diversity of genotypes within populations and their movement between populations by performing two large-scale population surveys (n = 58 populations) and assaying genotypic variation using random amplified polymorphic DNA (RAPDs). Contrary to expectations, sexually fertile populations did not exhibit higher genotypic diversity than sterile populations. For each cytotype, we detected one very common and widespread genotype. This would only occur with a very low probability (< 10-7) under regular sexual recombination. Compatibility analysis also indicated that the pattern of genotypic variation largely conformed to that expected with predominant clonal reproduction. The potential for recombination in diploids is not realized, possibly because seeds are outcompeted by bulbils for safe sites during establishment. We also failed to find evidence for more extensive movement of fertile than sterile genotypes. Aside from the few widespread genotypes, most were restricted to single populations. Genotypes in fertile populations were very strongly differentiated from those in sterile populations, suggesting that new triploids have not arisen during the colonization of North America. The colonization of North America involves two distinct forms of B. umbellatus that, despite striking reproductive differences, exhibit largely clonal population genetic structures.

Canada↗
PubMed1993

Lutzomyia longipalpis is a species complex: genetic divergence and interspecific hybrid sterility among three populations.

The sand fly Lutzomyia longipalpis is the vector of Leishmania donovani chagasi in Latin America. An analysis of genetic variability at 27 enzyme coding loci among three laboratory populations of Lu. longipalpis revealed substantial genetic polymorphism. Levels of genetic distance between all pairwise comparisons of colonies were very high, and consistent with those previously reported among separate species in the genus Lutzomyia. Between 7% and 22% of the loci studied were diagnostic for any two of the colony populations. Experimental hybridization between colonies resulted in the production of sexually sterile male progeny. Our results provide strong evidence that Lu. longipalpis exists in nature as a complex of at least three distinct species. The possible effects of colonization on the genetic makeup of laboratory populations is considered in extending our results to natural populations.

Animals↗
PubMed2005

Interaction between founder effect and selection during biological invasion in an aquatic plant.

Long-distance colonization and rapid range expansion associated with biological invasion may have major evolutionary consequences via both stochastic processes and selection. Using large-scale population genetic surveys, we demonstrate a major shift in the relative frequency of sexually fertile diploid versus sexually sterile triploid populations associated with the invasion of North America by a clonal aquatic plant, Butomus umbellatus. Most populations across the native European range were triploid (84% of 108), whereas most introduced populations were diploid (71% of 136). We evaluated the roles of stochastic processes versus natural selection in causing this shift by surveying predominantly neutral genetic variation at 28 RAPD loci. In Europe (EU) we detected 47 distinct genotypes among 142 plants sampled from 71 populations, whereas in North America (NA) we detected only six genotypes among 138 plants from 69 populations. Of the six NA genotypes, a set of four closely related genotypes were found only in triploid populations and a pair of closely related genotypes were found only in diploid populations, and these were genetically divergent from the triploid genotypes. This result is consistent with severe founder effect. Because sex creates genotypic variation and produces offspring with greater dispersal potential than those produced clonally, we tested the hypothesis that sexual reproduction characteristic of diploids has given them a colonization advantage that accounts for their high frequency in NA. However, we found little or no evidence of sexual recruitment in introduced diploids. One very widespread heterozygous genotype occurred in 95% of 38 introduced diploid populations (i.e., 72 of 76 plants surveyed) suggesting predominant clonal reproduction. Moreover genotypic diversity was not higher within or among diploid than triploid populations in either the native or introduced range. Low genetic diversity in diploid populations was also supported by a comparison of within-population quantitative variation for plant size under a common greenhouse environment. Thus, diploids have not been favored during colonization owing to their sexual fertility. However, concurrent studies have shown that NA diploids exhibit a much higher capacity for clonal reproduction, via small vegetative bulbils, than NA triploids, which almost never produce bulbils. The same difference in clonal capacity is not a consistent feature of the native EU populations. Taken together, these results suggest that strong founder effect has set the stage for a major increase in diploid frequency due to the particular, and possibly idiosyncratic, features of the diploid and triploid lineages introduced to North America.

Alismatales↗