Technique For Sex Determination Research Articles

An ARMS‐based technique for sex determination of red panda (Ailurus fulgens)

Molecular sexing is a key component in the investigation of wild populations. In this study, we developed a fast, accurate and reliable amplification refractory mutation system (ARMS) technique for sex determination of red panda based on the exon 4 of the ZFX/ZFY gene. The amplicons were distinguished simply by agarose gel electrophoresis, exhibiting one fragment in females (X: 300 bp) and two in males (X: 300 bp, Y: 166 bp). Robustness of this ARMS system was confirmed by testing both 43 captive red pandas using DNA samples with known-sex and 10 wild red pandas using faecal DNA samples with unknown sex.

Determination of sex by armbone dimensions

Sex determination is a vital part of the medico-legal system but can be difficult in cases where the body is damaged. The purpose of this study was to develop a technique for sex determination from three arm-bone dimensions (wrist circumference, arm length and arm span). This knowledge can be applied in cases of mass disaster, homicide and events such as sports. Data were collected for 95 Nigerian male students and 90 Nigerian female students using physical anthropometry. Discriminant function presented the wrist dimension as the dominant contributor in this study. Combination equations for both the wrist and arm-span dimensions correctly classified sex (male/female) with an accuracy rate of 84.9%. On cross-validation, sex was also established with the same 84.9% accuracy rate. Sex determination was higher in males. Sexual dimorphism was established in this study, although the wrist circumference was more distinct than arm span; a combination of both generated sex with an accuracy prediction rate of 84.9%.

Sex determination using metacarpal biometric data from the Athens Collection

Forensic anthropologists and bioarchaeologists usually determine sex by analyzing quantitative and qualitative characters of the human skeleton. In general, the pelvis and skull are the skeletal parts used most often, but in many cases these parts are missing or fragmentary. In such circumstances, it is necessary to use techniques based on other skeletal elements. The primary aim of this work is to determine whether metacarpals can be used for the determination of sex specifically in a Greek population. A secondary step is to describe and develop linear discriminant function equations for sex determination based on a contemporary Greek population using metacarpal biometric data. The skeletal sample of the modern Greeks is housed at the National and Kapodistrian University of Athens (NKUA) is comprised of 993 metacarpals (left and right), corresponding to 151 adult individuals (84 males and 67 females). The correct sex classification reached an accuracy of 83.7–88.1% for left and 83.8–89.7%, for right metacarpals. Our results suggest that metacarpals can be used for sexing in bioarchaeological, and forensic studies, in addition to other sex determination techniques.

Sex identification and software development using digital femoral head radiographs

The determination of sex is considered one of the first essential steps in positive identification. The current study aspires to accomplish a threefold purpose: to develop an easy and rapid sex determination technique using digital radiographs from the proximal epiphysis of the femur, to develop a simplified tool for pathologists that will provide accurate sex identification using radiographs and to compare this method with standard osteometric techniques applied to the same population. A total of 70 (36 males and 34 females) left femora were measured according to standard osteometric techniques. The proximal epiphyses of the same sample were then radiographed using a digital X-ray machine (TCA 4R PLUS). The skeletal remains were selected from the exhumed skeletons of St. Konstantinos and Pateles Cemeteries, Heraklion, Crete. Nine classical measurements were taken from the entire dry femora. Stepwise discriminant function analysis selected only 2 dimensions (maximum head diameter and anterior–posterior midshaft diameter) producing an accuracy rate of 88.6% for both original and cross-validated data. If assuming that only the proximal part of the femur is present, direct procedure results in 87.1% correct group membership. Six landmarks were selected in the radiograph and 15 variables representing all possible combinations of these landmarks were calculated using a specially designed calibrated Java program. Measurements were submitted to discriminant function analysis using SPSS subroutines. Stepwise discriminant function analysis selected only 3 out of 15 dimensions, producing an accuracy rate of 92.9%. The formula generated was then incorporated into the Java application, resulting in the development of a sex identification software (SIS). A sample of 36 (23 left and 13 right) femoral radiographs was used in order to test the software's reliability and sex was correctly identified in 32/36 cases, giving an accuracy rate of 91.7%. The radiographic technique proposed here performed better compared to conventional methods in the same population. From a forensic point of view it is a useful alternative method when semi-decomposed or charred remains are recovered in mass disasters or crime scenes and maceration is not an option. The application of metric methods in radiographs and the development of a highly specific software provides a useful and easy tool for sex identification that can be used in certain forensic cases in which osteometry does not apply.

Sex Determination from Hand Dimensions of North and South Indians

When dismembered human remains are encountered, the decedent's sex may not be obvious. For these scenarios, techniques for sex determination may play a vital part of the medicolegal investigation. Five hundred hands (230 males, 270 females) from North and South Indian region were studied to investigate sexual dimorphism in hand dimensions (hand length, hand breadth, and palm length). The hand index (hand breadth/hand length x 100) and the palm index (hand breadth/palm length x 100) were derived. The hand dimensions show a higher accuracy in sex determination when compared to indices. Of all hand dimensions, hand breadth has the highest accuracy of sex determination in the study group. The sex differences were found to be statistically significant only for the hand index on the left side. The morphometric parameters of the hand show considerable sexual dimorphism in the Indian population while the hand and palm index remain poor sex indicators. The study thus has medicolegal implications when a dismembered hand is brought for examination.

Sex identification of northern ungulates using low quality and quantity DNA

We evaluated PCR primer sets to determine the most effective technique for identifying sex of northern ungulates. We sought markers that required only a single pair of primers to amplify both X- and Y-linked alleles; that amplified X- and Y-linked products that were easily distinguishable using agarose gel electrophoresis; and that produced short amplicons amenable to amplification using DNA of poor quality and low quantity, as is often found in non-invasively collected samples such as feces. Primer pairs KY1/KY2 and SE47/SE48, which amplify X- and Y-specific alleles of the amelogenin gene, met our criteria and were tested for moose (Alces alces), mountain goat (Oreamnos americanus), Sitka black-tailed deer (Odocoileus hemionus sitkensis), and caribou (Rangifer tarandus). KY primers amplified shorter PCR products than did SE primers; moreover, SE primers inconsistently amplified certain Y-chromosome products, creating potential for misidentification of sex. DNA fragments amplified using KY primers were sequenced for each species, allowing us to characterize a 45-bp deletion for Y-linked alleles (136-bp product) relative to X-linked alleles (181-bp product) in all species and a 9-bp deletion in the X-linked allele of moose relative to other species. This is the first sex-determination technique using PCR reported for several ungulate species of Alaska. Although other protocols exist for cervids and bovids, this is the first report of markers meeting the aforementioned criteria for Odocoileus, the most abundant and intensively managed genus of large mammals in North America.

Craniometric analysis of the modern Cretan population

Despite the fact that sex assessment using craniofacial characteristics is commonly made worldwide, a lack of such investigation is noted in the Balkan area and in Greece in particular. The aim of this study is to develop a sex determination technique using osteometric data from skeletal remains of a contemporary Cretan cemetery population. A total of 90 males and 88 females are measured according to standard osteometric techniques. Age differences are not significant (mean age for men = 68.94 ± 13.41, N = 66; for women = 73.21 ± 16.77, N = 66). A total of 16 dimensions taken from the craniofacial skeleton are used and data are analyzed using SPSS subroutines. A comparison is made with other contemporary populations, including Americans (Terry collection) and South Africans (Dart and Pretoria collections), as well as an archaeological sample (Middle and Late Helladic) from Crete. Results indicate that males are statistically significantly greater than females in all dimensions. Bizygomatic breadth is the most discriminatory single dimension and can provide an accuracy rate of 82% on average. Using a stepwise method involving five dimensions (bizygomatic breadth, cranial length, nasion–prosthion and mastoid height and nasal breadth), accuracy is raised to 88.2%. Interestingly, cranial length is selected as the first discriminating variable by the stepwise analysis when only the neurocranium is available for measurement.

Evolution of Prenatal Diagnostic Techniques From Phenotypic Diagnosis to Gene Arrays: Its Likely Impact on Prenatal Diagnosis of Hemophilia

Prenatal diagnostic techniques in hemophilia have evolved through the early sex-determination techniques of offering a nonspecific diagnosis in case of a male fetus through the various mutation screening techniques to the more recent gene array techniques. Each of these techniques has specific advantages and disadvantages. The sampling techniques have evolved simultaneously to suit the requirements of each technique and also the different gestation periods. The DNA-based testing methods provide a range of aberrations detected with different levels of genomic resolution. The more recent gene array analysis is poised to have substantial impact on prenatal diagnosis of hemophilia not only in studying the highly heterogeneous mutations but may also be useful in studying the effect of various ameliorating or epistatic genetic mutations/ polymorphisms simultaneously, providing a wide range of options to the prenatal diagnosis experts, the genetic counselors, and the couples opting for prenatal diagnosis.

A reliable genetic technique for sex determination of giant panda (Ailuropoda melanoleuca) from non-invasively collected hair samples

Extractions from non-invasive hair samples usually yield low amounts of highly degraded DNA. Previously developed mammal molecular sexing methods were not designed with such sub-optimal conditions in mind. We developed a simple and reliable PCR-based sexing method aimed at degraded, low yield DNA extractions from the giant panda (Ailuropoda melanoleuca). Comparisons of this new primer set with others showed that the reliability of sex determination from low-yield, degraded DNA extractions was improved if; amplification products were short (<170 bp); and the Y-chromosome amplification product was shorter than the X-chromosome amplification product. The primers developed in this study appear useful for sex determination in other bear species.

A PCR-based sex determination method for possible application in caprine gender selection by simultaneous amplification of the Sry and Aml-X genes.

Sex determination of livestock is performed to achieve the objectives of livestock breeding programmes. Techniques for sex determination have evolved from karyotyping to detecting Y-specific antigens and recently to the polymerase chain reaction (PCR), which appears to be the most sensitive, accurate, rapid and reliable method to date. In this study, a PCR-based sex determination method for potential application in goat breeding programmes was developed. Primers were designed to amplify a portion of the X amelogenin gene (Aml-X) on the X chromosome to give a 300 bp product and Sry gene on the Y chromosome to give a 116 bp product. PCR optimization was performed using DNA template extracted from a whole blood sample of Jermasia goats (German Fawn x Katjang) of both sexes. It was possible to identify the sex chromosomes by amplifying both male- and female-specific genes simultaneously in a duplex reaction with males yielding two bands and females yielding one band. The Aml-X primer set, which served as an internal control primer, did not interfere with amplification of the Y-specific sequence even when a low amount of DNA (1 ng) was used. The duplex reaction subjected to a blind test showed 100% (14/14) concordance, proving its accuracy and reliability. The primer sets used were found to be highly specific and were suitable for gender selection of goats.

Determining Sex of Magellanic Penguins Using Molecular Procedures and Discriminant Functions

Abstract Magellanic Penguins (Spheniscus magellanicus) show little sexual dimorphism, and although males are usually larger than females, sexing by direct observation may be difficult, especially in the case of chicks. In this paper we evaluate the utility of four different PCR-based sex determination techniques using genomic DNA for sexing Magellanic Penguins. We found that the primer set designed for sex determination in Collared Flycatcher (Ficedula albicollis) also provided a reliable, simple and convenient sexing procedure for Magellanic Penguins. Additionally, we obtained discriminant functions for sexing adults and chicks, sampled at six colonies differing in size and other ecological characteristics. Discriminant function for adults used two variables, bill length and bill depth that correctly classified 97% of the birds. Discriminant function for chicks included bill length and flipper length and correctly classified 78% of the individuals. Although molecular and biometric approaches could be use...

Nonelectrophoretic PCR-sexing of bovine embryos in a commercial environment

Techniques for sex determination of bovine embryos have evolved from karyotyping of older preimplantation embryos some 25 years ago to the current variety of widely used polymerase chain reaction (PCR) protocols. Although highly accurate, most PCR protocols for sex determination have included an electrophoresis step. The present work is a retrospective study utilizing a unique PCR protocol to sex bovine embryos without use of electrophoresis in a commercial embryo transfer program. Both in vivo and in vitro-derived embryos were produced by conventional techniques and biopsied between 7 and 8 days of age with a steel blade attached to a mechanical micromanipulator. Males constituted 49.0% of 3964 in vivo and 53.0% of 1181 in vitro-derived embryos subjected to PCR. Based on ultrasound fetal sexing and on calvings, the accuracy of sex determination was 98.7% for male embryos and 94.4% for females, with no samples producing an undetermined outcome. Pregnancy rates following transfer of biopsied Grade 1 embryos were lower than control, intact embryos as follows: 8, 6 and 16% points for in vivo, in vitro and in vivo frozen embryos, respectively. Pregnancy rates were similar for all stages of in vivo-derived embryos, whereas the pregnancy rate was significantly lower for in vitro-derived morulae compared to all stages of blastocysts. The sex ratio was significantly skewed in favor of females among in vitro-derived morulae, and in favor of males among in vitro expanded blastocysts. The sex ratio of in vivo expanded blastocysts was significantly skewed in favor of female embryos. No seasonal variation in either pregnancy rate or sex ratio was detected. There was no evidence that DNA contamination influenced the PCR assay during the duration of the study. The assay was sensitive to single blastomeres from male embryos, whereas it was not sensitive to Percoll®-centrifuged or accessory sperm cells.

ESTIMATING SEX OF MAYA SKELETONS BY DISCRIMINANT FUNCTION ANALYSIS OF LONG-BONE MEASUREMENTS FROM THE PROTOHISTORIC MAYA SITE OF TIPU, BELIZE

Discriminant functions were developed using long-bone robusticity measurements of 82 individuals from the protohistoric Maya site of Tipu, Belize. All individuals were sexed using nonmetric morphological indicators, particularly those of the pelvis. These functions are designed to provide a means of determining the sex of fragmentary prehistoric Maya skeletons. The equations ranged in accuracy from 77.5% to 100%. The reliability of these equations was tested using a jackknife method on the Tipu sample and by applying the equations to small samples of prehistoric skeletons from the sites of Seibal, KOB Swamp, Laguna de On, and Chau Hiix. The vast majority of the equations applied to the test cases succeeded in correctly estimating the sex based on pelvic and cranial features. A more reliable technique for sex determination of poorly preserved skeletal remains will allow a whole new range of archaeological and bioanthropological hypotheses concerning sex and gender among the ancient Maya to be investigated and considered.

The Assessment of Sex in Cremated Individuals: Some Cautionary Notes

ABSTRACTIdentification of cremated bodies is problematic due to the effect of burning on the tissues of the body. Since hard tissues are altered by burning, it is likely that identification techniques that rely on these tissues will also be affected. The purpose of this study is to examine how heat-induced changes in the hard tissues of the body influence the results of anthropological methods of analysis. Twelve sheep Os coxae were burned in a fire-brick furnace. Eight measurements were taken from the sheep Os coxae before ànd after burning. Heat-induced shrinkage was calculated as a percentage. The significance of the differences between the measurements taken before and after burning was assessed statistically (Wilcoxon Signed Rank). The alternative hypothesis, that the difference was significant, was accepted. The influence of heat-induced shrinkage on sex assessment techniques was examined algebraically, then demonstrated with metric methods of sex assessment. The conclusion reached was that uniform shrinkage of the pelvis would not affect metric sex determination techniques, but that differential shrinkage of the variables that comprise the metric sex assessment technique can result in misclassification of male cremated pelves as female, and vice versa.

Efficacy of sex determination in the greater cane rat, Thryonomys swinderianus, Temminck.

The efficacy of the two most common techniques used for determining the sex of the greater cane rat, Thryonomys swinderianus, Temminck, was tested using 10 young and 8 adult animals with two technicians at the Animal Research Institute's Grasscutter Domestication Centre, Pokoase, Ghana. The techniques compared were the use of the head shape and/or head size and the use of the ano-genital distance. The use of the ano-genital distance for sex determination was validated in a colony of greater cane rats at various stages of development, i.e. from the day of birth to three or more years of age. The ano-genital distance was then used as the standard against which the use of the head shape and/or head size technique was tested. The results indicated that the use of the ano-genital distance for sex determination in the greater cane rat was error-free, even with little experience on the part of the practitioner. The ano-genital distance was more than twice as long in the males than in the females at all ages (p < 0.001). However, the use of the head shape and/or head size for sex determination was found to be associated with some degree of error in both sexes. The use of the ano-genital distance can therefore be recommended as an efficacious technique for sex determination in the greater cane rat.

An approach to sexing young Great Bustards Otis tarda using discriminant analysis and molecular techniques

Adult Great Bustards Otis tarda are sexually dimorphic, males weighing more than twice as much as females. However, there is no practical way to distinguish sex in chicks by their morphology. In this paper we describe a discriminant function, Tail Length/Weight, which correctly sexed 98.2% of 165 Great Bustard chicks at two study areas in Spain, the Wildlife Reserve of Lagunas de Villafáfila and the province of Madrid. The value for Tail Length/Weight separating the sexes was 0.099: Tail Length/Weight for males < 0.099 < Tail Length/Weight for females. We also show that the recently described PCR-based sex determination technique using genomic DNA is valid for the Great Bustard. Both approaches should be useful for sexing young Great Bustards in captive breeding programmes and studies on wild populations.

Osteometric variation in the humerus: sexual dimorphism in South Africans.

There has been a surge of research on forensic anthropology in South Africa. Differences between the populations of this country and others are demonstrated in many studies. Yet, many forensic osteometric techniques based on other populations are still in use. The purpose of the present study is to develop an osteometric sex determination technique using the humerus. The sample is composed of skeletons of 104 whites and 88 blacks from the Dart and Pretoria collections. Six humeral dimensions were initially analyzed using stepwise discriminant function statistics. Humeral head diameter, deltoid tuberosity circumference and epicondylar breadth were individually calculated in order to make the technique usable for fragmented remains. The results indicated that the head and epicondylar diameters are the best in whites to differentiate sexes from each other, while head diameter and maximum length are best in blacks. Accuracy of correct classification was as high as 96% in whites and 95% in blacks. Crossvalidation provided the same accuracy as the original classification. These accuracy percentages are as high as those expected from the femur and tibia. Posterior probability, which measures the percent affiliation of the sample with its original sex group, was also mostly 80% or better. South African collections are ideal for osteometric analysis, because they are still growing in numbers with cross-sectional representatives from the country.

Sex identification in the moorhen (Gallinula chloropus) by flow cytometry and morphometric analysis

Sexing individuals in a population is important in many ecological and life‐history studies. Since many bird species are monomorphic, non‐invasive tools are necessary for sex determination. In this study we utilized flow cytometry to sex individuals in a moorhen population of northern Italy. By improving previous laboratory protocols, we were able to obtain clear and repeatable measures of DNA content from field blood samples. The per cent difference in nuclear content between male and female moorhens was among the highest values reported for birds. We also utilized a discriminant analysis of seven morphological measures to investigate whether birds can be sexed on the basis of biometry. Tarsus and foot lengths were the most influential variables in gender discrimination. However, only 13 females and 10 males (77%) were correctly sexed, while six females and two males were wrongly assigned. When juvenile moorhens were excluded the discriminant analysis correctly sexed 90% of the birds. Since morphometric comparisons with English moorhen populations showed that discriminant bio‐metrical values are geographically different, and thus not useful as universal sexing tools, we recommend the use of the cytometry technique for sex determination.

Evaluation of the Human Hair Root for DNA Typing Subsequent to Microscopic Comparison

Telogen human hairs are one of the most common useful evidence findings at crime scenes and/or on homicide victims. Occasionally, the microscopic characterization of the found telogen hair is the only physical evidence association to a victim or suspect. Recently efforts to characterize these hairs by mitochondrial DNA (mtDNA) methods have progressed. The nature of the telogen hair root morphology and ultrastructure has, however, been largely ignored. Examiners have recognized these hairs are unlikely to be typable by nuclear DNA (nuDNA) methods. Most forensic biologists have little knowledge of the complex cellular composition of anagen, catagen, and telogen hair roots or their morphogenesis. This paper reviews ex situ human hair root morphology as it relates to the likelihood of successful nuclear DNA typing. Dermatology texts of hair root morphology always demonstrate their microscopic appearance in the skin. This study investigates the use of fluorescence in situ hybridization (FISH) methods to sex type telogen head hairs, and it further investigates hair root morphology as it relates to the potential nuclear DNA content of evidence hairs. There is a need for the use of appropriate, consensus terminology for describing hair root morphology. There is also a need for standardized laboratory light microscopic methods in evaluating a hair root for DNA typing. FISH was found to be an unsuitable technique for sex determination of telogen hair clubs. It was determined that anagen/catagen hair roots without translucent sheath material are excellent candidates for nuDNA PCR-based typing and that hairs with telogen club root material only should not be submitted for nuDNA typing attempts.

A Case of Problematic Diffusion

Sex determination techniques have diffused rapidly in India, and are being used to detect female fetuses and subsequently to abort them. This technology has spread rapidly because it imparts knowledge that is of great value within the Indian context, and because it fits in neatly with the modernization dynamic within India, which itself has enmeshed with traditional patriarchal institutions to oppress Indian women. More research needs to be done on ways to stem the adoption of problematic innovations.