Analysis of ancient DNA from a prehistoric Amerindian cemetery.
The Norris Farms No. 36 cemetery in central Illinois has been the subject of considerable archaeological and genetic research. Both mitochondrial DNA (mtDNA) and nuclear DNA have been examined in this 700-year-old population. DNA preservation at the site was good, with about 70% of the samples producing mtDNA results and approximately 15% yielding nuclear DNA data. All four of the major Amerindian mtDNA haplogroups were found, in addition to a fifth haplogroup. Sequences of the first hypervariable region of the mtDNA control region revealed a high level of diversity in the Norris Farms population and confirmed that the fifth haplogroup associates with Mongolian sequences and hence is probably authentic. Other than a possible reduction in the number of rare mtDNA lineages in many populations, it does not appear as if European contact significantly altered patterns of Amerindian mtDNA variation, despite the large decrease in population size that occurred. For nuclear DNA analysis, a novel method for DNA-based sex identification that uses nucleotide differences between the X and Y copies of the amelogenin gene was developed and applied successfully in approximately 20 individuals. Despite the well-known problems of poor DNA preservation and the ever-present possibility of contamination with modern DNA, genetic analysis of the Norris Farms No. 36 population demonstrates that ancient DNA can be a fruitful source of new insights into prehistoric populations. (+info)
Transcervical recovery of fetal cells from the lower uterine pole: reliability of recovery and histological/immunocytochemical analysis of recovered cell populations.
The aim of this work was to isolate, enumerate and attempt the identification of fetal cells recovered from the lower uterine pole. Immediately before elective termination of pregnancy at 7-17 weeks gestation, samples were recovered by transcervical flushing of the lower uterine pole (n = 108) or transcervical aspiration of mucus from just above the internal os (n = 187), and their contents examined using histological, immunohistochemical and molecular techniques. Syncytiotrophoblasts were identified morphologically in 28 out of 89 (31%) and 50 out of 180 (28%) flushings and aspirates respectively (mean 29%). Immunocytochemistry with monoclonal antibodies (mAbs) recognizing trophoblast or epithelial cell antigens on a smaller number of samples (n = 69) identified putative placental cells in 13 out of 19 (68%) and 25 out of 50 (50%) flushings and aspirates respectively (mean 55%). These included groups of distinctive cells with a small, round, hyperchromatic nucleus, strongly reactive with mAbs PLAP, NDOG1 and FT1.41.1. Smaller groups of larger, amorphous cells, usually containing multiple large, pale staining nuclei, reactive with mAb 340 and to a lesser degree with mAb NDOG5 were also observed. Taking cellular morphology and immunophenotype into consideration, the smaller uninucleate cells were likely to be villous mesenchymal cells, while the larger cells were possibly degrading villous syncytiotrophoblast. There was no significant difference in the frequency of fetal cells obtained by the two recovery methods. Squamous or columnar epithelial cells, labelled strongly with antibodies to cytokeratins or human milk fat globule protein, were observed in 97% (29 out of 30) of aspirates. The use of cervagem in a small number of patients prior to termination of pregnancy did not appear to influence the subsequent recovery of placental cells. Y-specific DNA was detected by polymerase chain reaction (PCR) in 13 out of 26 (50%) flushings and (99 out of 154) 64% aspirates analysed (mean 62%). In-situ hybridization (ISH) revealed Y-specific targets in 40 out of 69 (60%) of aspirates analysed. A comparison of PCR data obtained from transcervical recovered samples and placental tissues showed a concordance of 80% (76 out of 95), with 10 false positives. Comparing the PCR data from tissues with data derived by ISH from 41 aspirates gave a concordance of 90% with two false positives. Although syncytiotrophoblasts were much more likely to be present in samples containing immunoreactive placental cells, the detection rates of fetal-derived DNA were similar regardless of the morphological and/or immunological presence of placental cells. We conclude that the transcervical recovery of fetal cells, while promising, requires considerable additional effort being expended in further research and development, particular in the sampling procedure. (+info)
International developments in abortion law from 1988 to 1998.
OBJECTIVES: In 2 successive decades since 1967, legal accommodation of abortion has grown in many countries. The objective of this study was to assess whether liberalizing trends have been maintained in the last decade and whether increased protection of women's human rights has influenced legal reform. METHODS: A worldwide review was conducted of legislation and judicial rulings affecting abortion, and legal reforms were measured against governmental commitments made under international human rights treaties and at United Nations conferences. RESULTS: Since 1987, 26 jurisdictions have extended grounds for lawful abortion, and 4 countries have restricted grounds. Additional limits on access to legal abortion services include restrictions on funding of services, mandatory counseling and reflection delay requirements, third-party authorizations, and blockades of abortion clinics. CONCLUSIONS: Progressive liberalization has moved abortion laws from a focus on punishment toward concern with women's health and welfare and with their human rights. However, widespread maternal mortality and morbidity show that reform must be accompanied by accessible abortion services and improved contraceptive care and information. (+info)
Reconstruction of a historical genealogy by means of STR analysis and Y-haplotyping of ancient DNA.
Archaeological excavations in St Margaretha's church at Reichersdorf, Germany, in 1993 led to the discovery of eight skeletons, so far assumed to be of the Earls of Konigsfeld, who used the church as a family sepulchre over a period of seven generations from 1546 to 1749. DNA-based sex testing and analysis of autosomal short tandem repeat systems (STR) was carried out to confirm the assumption of kinship. Since five of the individuals were determined as males, analysis of Y-specific STRs seemed feasible. A comparison of Y-haplotypes revealed that one individual could not be linked to the Konigsfeld patrilineage, an observation supported by autosomal STR evidence. Two individuals typed as females posed an identification problem, since supposedly only male members of the family were buried in St Margaretha's. Nevertheless, these individuals could tentatively be identified as members of the House of Konigsfeld through genetic fingerprinting. (+info)
The sonographic identification of fetal gender from 11 to 14 weeks of gestation.
OBJECTIVE: To determine the feasibility of correctly identifying fetal gender from 11 to 14 weeks' gestation. METHODS: A prospective cross-sectional study in a university Department of Obstetrics and Gynaecology, London. A total of 524 women from an unselected population underwent a detailed assessment of fetal anatomy at 11-14 weeks of gestation (confirmed by crown-rump length) by means of transabdominal sonography, and transvaginal sonography (26%) when necessary. Fetal gender was identified in the transverse and sagittal planes, and was confirmed at birth. RESULTS: The overall success of correctly assigning fetal gender increased with gestational age from 46% to 75%, 79% and 90% at 11, 12, 13 and 14 weeks, respectively. The ability of the operator to assign fetal gender significantly improved with increasing gestational age (p < 0.0001), being 59%, 87%, 92% and 98% at 11, 12, 13 and 14 weeks, respectively. The accuracy of correctly identifying fetal gender when attempted did not change with gestational age. Fetal gender or the performance of the scan by different operators did not affect the results. CONCLUSION: Whilst the accuracy of sonographic determination of fetal gender at 11-14 weeks is good, it still falls significantly short of invasive karyotyping tests. (+info)
First-trimester determination of fetal gender by ultrasound.
OBJECTIVE: To assess the accuracy of fetal sex determination at 11-14 weeks of gestation. METHODS: Fetal gender assessment by ultrasound was prospectively carried out in 172 singleton pregnancies at 11-14 weeks of gestation immediately before chorionic villus sampling for karyotyping. The genital region was examined in a midsagittal plane and the fetal gender was assigned as male if the angle of the genital tubercle to a horizontal line through the lumbosacral skin surface was greater than 30 degrees and female when the genital tubercle was parallel or convergent (less than 30 degrees) to the horizontal line. RESULTS: The accuracy of sex determination increased with gestation from 70.3% at 11 weeks, to 98.7% at 12 weeks and 100% at 13 weeks. In the male fetuses, there was a significant increase in the angle of the genital tubercle from the horizontal with crown-rump length. Male fetuses were wrongly assigned as female in 56% of cases at 11 weeks, 3% at 12 weeks and 0% at 13 weeks. In contrast, only 5% of the female fetuses at 11 weeks were incorrectly assigned as male and this false-positive rate was 0% at 12 and 13 weeks. CONCLUSION: The clinical value of determination of fetal sex by ultrasound is in deciding whether to carry out prenatal invasive testing in pregnancies at risk of sex-linked genetic abnormalities, because invasive testing would be necessary only in pregnancies with male fetuses. Our results suggest that a final decision on invasive testing for sex-linked conditions should be undertaken only after 12 weeks of gestation. (+info)
Biometrical threshold of biparietal diameter for certain fetal sex assignment by ultrasound.
OBJECTIVES: The aim of this study was to establish the biometric threshold of biparietal diameter (BPD), assumed to be an independent variable of gestational age, at which 100% accuracy in the assessment of fetal sex by ultrasonography is achievable. METHODS: Transvaginal and/or transabdominal sonography was used for detecting the 'sagittal sign' as a marker of fetal sex in 385 fetuses with BPD between 18 and 29 mm. The results of ultrasound examination were compared with sex at birth or with karyotype obtained from amniotic fluid cells or chorionic villus sampling. RESULTS: Fetal sex assignment was feasible in 337 of 385 cases (87.5%). Of the 312 fetuses with known fetal sex outcome, 164 were males and 148 were females. An accuracy rate of 100% was achieved when a BPD of > or = 23 mm was obtained. CONCLUSION: This study provides important information about the earliest stage of fetal development, expressed in terms of BPD, at which a diagnosis of fetal sex can be made with 100% accuracy. (+info)
Mutations affecting sexual development in Phycomyces blakesleeanus.
Although zygospore (mature zygote) formation in P. blakeslleeanus occurs in liquid glucoseglutamate medium, morphological observations are made more easily when cultures are grown on 1-mm-thick agar medium. Zygophores (sexually differentiated hyphae) develop prior to physical contact in crosses of (plus) and (minus) wild types. Zygophores interlock upon contact and then undergo six successive morphological changes to become a zygospore. Mutants with abnormal carotene synthesis exhibit aberrant sexual behavior. Some zygospores do form in crosses of carA mutants and wild types. Only paired zygophores form in crosses of wild type(plus) with car-42(minus), a beta-carotene-accumulating mutant. Zygophores form only on (minus) in crosses of wild type(plus) with carB(minus), carR(minus), carAcarR(minus), and carBcarR(minus) mutants, and only on (plus) in crosses of car-43(plus) with wild type(minus), car-42(minus), and carA(minus) mutants. Zygophores do not form in crosses of car-43(plus) with carB(minus), carR(minus), carAcarR(minus), and carBcarR(minus) mutants. These observations demonstrate that each mating type makes a chemical messenger that stimulates zygophore development in the opposite mating type. (+info)