ON THE SOUTH AFRICAN RACE OF THE LITTLE SPOTTED WOODPECKER

Discriminant analysis functions have previously been determined for sexing Mediterranean Yellow-legged Gulls Larus michahellis michahellis from the western Mediterranean basin. However, data from eastern Mediterranean populations are lacking. In this work, we used morphometric data from a sample of 81 Mediterranean Yellow-legged Gulls (39 males and 42 females) breeding in the Gulf of Gabès in south-eastern Tunisia to (1) determine a discriminant function useful for sex discrimination, and (2) assess the accuracy of previously published functions in sexing Mediterranean Yellow-legged Gulls from our study area. Our results showed marked sexual differences in all morphological measurements, with males being significantly larger than females. The best discriminant function included head length, bill depth and wing length, and accurately classified 93% of sampled birds. We also found that Mediterranean Yellow-legged Gulls from the Gulf of Gabès could accurately be sexed using discriminant functions determined for another North African population, but not with a function determined for a South European population, although distances between sites are almost the same.     

Efficacy of a commercially available post-thaw bovine semen sexing kit in both single-ovulating and hyperstimulated cows

Currently, there are few inexpensive, reliable, effective methods for commercially separating X- and Y-chromosome bearing fresh and frozen bovine sperm. The objective of these experiments was to determine the efficacy of a commercially available post-thaw bovine semen sexing kit, HeiferPlus™ (HP) which claims to alter the sex ratio in favor of female calves following artificial insemination. Three trials included the insemination of hyperstimulated cows with Control or HP-treated semen, non-surgical embryo collection on Day 7, and a combined PCR/dot blot assay to determine embryo sex. Chi-square analysis showed that the Control group produced a greater proportion (p < 0.0005) of female embryos than the HP group. There were no differences in the proportions of transferable compared with degenerate embryos or in number of ovulations, embryos, and unfertilized ova collected from Control compared with HP groups. When treatments were combined, one of the two bulls used in the hyperstimulation studies produced an overall greater proportion of females (p < 0.05), suggesting a bull effect.Another trial involved the insemination of cows synchronized via OvSynch^® with fetal sexing via ultrasonography. Results of these studies indicated that HP semen sexing kit did not alter the sex ratio in favor of females in either hyperstimulated or single-ovulating cows; however, potential bull effects may be further evaluated to understand the capacity of HP with semen from specific bulls. Additionally, perhaps the sex of the surviving embryo can be manipulated by the maternal side, through ovarian, hormonal, oviductal, or uterine influences.     

Effects of age and occupation on cortical bone in a group of 18th-19th century British men

The effects of age and occupation on cortical bone in a group of adult males from the 18th-19th century AD skeletal collection from Christ Church Spitalfields, London, were investigated. Cortical bone was monitored using metacarpal radiogrammetry. Individual age at death was known exactly from coffin plates. Occupation for individuals was known from historical sources. Results showed that continued periosteal apposition was evident throughout adult life, but from middle age onwards this was outstripped by about 2:1 by endosteal resorption, so that there was net thinning of cortical bone. The rate of cortical thinning resembled that seen in modern European males. Cross-sectional properties, as measured by second moments of area, bore no relationship to occupation. The results may suggest that, firstly, patterns of loss of cortical bone have remained unchanged in males for at least two centuries in Britain, and secondly, that biomechanical analyses of metacarpal cortical bone may be rather insensitive indicators of intensity of manual activity.     

哺乳类性别控制的实践与进展

动物的性别控制是指通过对精子或胚胎的性别鉴定以达到调控子代性别的目的。基于在人类健康及畜牧业生产上的应用价值,动物的性别控制一直是人类期望达到的目标之一。介绍了性别控制的研究历史及最新进展,并着重就不同性别控制手段的理论基础,特点,实践应用价值及未来发展进行了评述。     

PCR-based sexing in conservation biology: Wrong answers from an accurate methodology?

Molecular tests of sex based on the polymerase chain reaction (PCR) are now commonplace in conservation biology, routinely guiding management decisions. While molecular approaches to sexing can be highly reliable, current practices may leave an undesirable level of uncertainty in the sexes identified, because researchers focus on determining the sex-specific nature of a test, largely ignoring the accuracy of the test to correctly sex individuals. This latter step requires considerably more known-sex individuals. We argue that, due to the well-known technical problems associated with PCR amplification, the demonstrated potential for sexing errors and few known-sex individuals being available from threatened species, conservationists should place greater emphasis on verifying the sexes identified with PCR tests. We propose that all individuals of the sex indistinguishable from an amplification failure (e.g., females in mammals XX, males in birds ZZ) should be verified with a second independent sex test. Such a consensus approach to molecular sexing would reduce errors that could arise due to technical failure and PCR anomalies, but may also reduce field and laboratory bookkeeping errors.     

Improving the reliability of molecular sexing of birds using a W-specific marker

Molecular techniques for identifying sex of birds utilize length differences between CHD-Z and CHD-W introns, but in some cases these methods can lead to sexing errors. Here we show that an additional W-specific primer can be used in conjunction with a pre-existing sexing primer pair to dramatically improve the reliability of molecular sexing methods. We illustrate the approach with American coots (Fulica americana), a species with CHD-Z polymorphism that could not be accurately sexed using traditional methods. We developed a reverse primer GWR2 designed to sit within the intron of the W chromosome and amplify a distinctively small DNA fragment that serves as a W-specific marker. Analysis of known-sex individuals indicates that this W-specific primer provides an efficient and reliable protocol to identify the sex of F. americana. The development of such sex-specific primers will likely increase the reliability of molecular sexing methods in other birds as well. Comparisons between CHD-Z alleles of coots and common moorhens (Gallinula chloropus) revealed that CHD-Z polymorphism evolved separately in these two closely related species. We discuss the implications of repeated evolution of CHD-Z polymorphisms among birds.     

Morphological Correlates of Speciation in Bush Babies

Morphology is not a reliable specific indicator in nocturnal animals. Nevertheless, because species are genetically independent, appropriate analytic methods should reveal subtle and consistent morphological differences among them. Until recently, the diversity of living bush babies was underrated, and new species have been recognized on the basis of genetic, behavioral and soft tissue data. This has placed museum curators in a quandary as to how to sort their skin and skull collections according to the new specific designations.We conducted multivariate analyses of 6 morphologically similar pairs of bush baby taxa: Otolemur crassicaudatus and O. garnettii; Galagoides demidoffand G. thomasi; Galago gallarumand G. senegalensis; G. moholi and G. senegalensis; Euoticus elegantulus and E. pallidus, and Galagoides zanzibaricus and G. granti. We also compared subspecies within the taxa Otolemur crassicaudatus, O. garnettii, Galagoides demidoff, and Galago senegalensis.Five out of six species pairs were discriminated with a high level of reliability (88.5–99%) on the basis of 2–5 morphological variables. Only Euoticus elegantulus and E. pallidus did not show this pattern. All strongly supported specific discriminations share two features: (a) ear length is a highly significant factor, while the involvement of other characters is variable; (b) the greater the reliability of the discrimination, the fewer variables necessary to effect it. Euoticus elegantulus and E. pallidus behaved more like subspecies in the discrimination, while Galago senegalensis sspp. showed a pattern of variation similar to that in the specific analyses.     

Application of the Bang and Ramm age at death estimation method to two known‐age archaeological assemblages

The Bang and Ramm method uses root dentine translucency (RDT) length in sectioned or unsectioned teeth as a sole indicator of chronological age at death in adult human remains. The formulae have been tested on modern remains of known age and on modern and archaeological remains of unknown age. This is the first published study of the method on known‐age archaeological specimens and tests whether RDT is a good indicator of chronological age in buried human remains. We applied the Bang and Ramm equations to two 18th and 19th century assemblages excavated from the crypt of Christ Church, Spitalfields, and the cemetery of All Hallows by the Tower. Translucency was defined by shining a light through the external unsectioned root surface and was measured from digital images of 583 and 83 nonmolar roots from 126 Spitalfields and 12 All Hallows individuals, respectively, aged 21–81 years. Average absolute difference between real age and estimated age was 10.7 years and 8.4 years for Spitalfields and All Hallows individuals, respectively, with 58% and 75% estimated within 10 years of known age, and 29% and 33% estimated within five years of known age. These estimations are comparable to results from other ageing methods applied to the Spitalfields collection. Ages from both populations were estimated largely to the middle ranges, with younger individuals overestimated and older individuals underestimated. This is a common occurrence when using inverse calibration, where age is treated as the dependent variable and the ageing feature as the independent variable. Am J Phys Anthropol 155:332–351, 2014. © 2014 Wiley Periodicals, Inc.