pSTAT3 activation of Foxl2 initiates the female pathway underlying temperature-dependent sex determination.

Ovarian development was traditionally recognized as a "default" sexual outcome and therefore received much less scientific attention than testis development. In turtles with temperature-dependent sex determination (TSD), how the female pathway is initiated to induce ovary development remains unknown. In this study, we have found that phosphorylation of the signal transducer and activator of transcription 3 (pSTAT3) and Foxl2 exhibit temperature-dependent sexually dimorphic patterns and tempo-spatial coexpression in early embryos of the red-eared slider turtle (Trachemys scripta elegans). Inhibition of pSTAT3 at a female-producing temperature of 31 °C induces 64.7% female-to-male sex reversal, whereas activation of pSTAT3 at a male-producing temperature of 26 °C triggers 75.6% male-to-female sex reversal. In addition, pSTAT3 directly binds to the locus of the female sex-determining gene Foxl2 and promotes Foxl2 transcription. Overexpression or knockdown of Foxl2 can rescue the sex reversal induced by inhibition or activation of pSTAT3. This study has established a direct genetic link between warm temperature-induced STAT3 phosphorylation and female pathway initiation in a TSD system, highlighting the critical role of pSTAT3 in the cross talk between female and male pathways.

Overexpression of Kdm6b induces testicular differentiation in a temperature-dependent sex determination system.

In reptiles, such as the red-eared slider turtle ( Trachemys scripta elegans), gonadal sex determination is highly dependent on the environmental temperature during embryonic stages. This complex process, which leads to differentiation into either testes or ovaries, is governed by the finely tuned expression of upstream genes, notably the testis-promoting gene Dmrt1 and the ovary-promoting gene Foxl2. Recent studies have identified epigenetic regulation as a crucial factor in testis development, with the H3K27me3 demethylase KDM6B being essential for Dmrt1 expression in T. s. elegans. However, whether KDM6B alone can induce testicular differentiation remains unclear. In this study, we found that overexpression of Kdm6b in T. s. elegans embryos induced the male development pathway, accompanied by a rapid increase in the gonadal expression of Dmrt1 at 31°C, a temperature typically resulting in female development. Notably, this sex reversal could be entirely rescued by Dmrt1 knockdown. These findings demonstrate that Kdm6b is sufficient for commitment to the male pathway, underscoring its role as a critical epigenetic regulator in the sex determination of the red-eared slider turtle.

Genome assemblies for Chromidotilapia guntheri (Teleostei: Cichlidae) identify a novel candidate gene for vertebrate sex determination, RIN3.

Advances in genome sequencing have greatly accelerated the identification of sex chromosomes in a variety of species. Many of these species have experienced structural rearrangements that reduce recombination between the sex chromosomes, allowing the accumulation of sequence differences over many megabases. Identification of the genes that are responsible for sex determination within these sometimes large regions has proved difficult. Here, we identify an XY sex chromosome system on LG19 in the West African cichlid fish Chromidotilapia guntheri in which the region of differentiation extends over less than 400 kb. We develop high-quality male and female genome assemblies for this species, which confirm the absence of structural variants, and which facilitate the annotation of genes in the region. The peak of differentiation lies within rin3, which has experienced several debilitating mutations on the Y chromosome. We suggest two hypotheses about how these mutations might disrupt endocytosis, leading to Mendelian effects on sexual development.

Cephalometric Analysis of Maxillary Sinus for Gender Determination Using Lateral Cephalogram: A Novel Retrospective Study in the North Indian Population.

BACKGROUND: Underlying disorders of the maxillary sinus (MS), including a history of sinus surgeries, chronic sinusitis, or congenital anomalies can potentially impact sinus function and structure, necessitating careful evaluation and management. Moreover, intact sinuses are crucial in gender determination in forensic anthropology. The present study was undertaken to check the accuracy and reliability of MS in gender determination using morphometric parameters. MATERIALS AND METHODS: This retrospective study was carried out on 74 lateral cephalograms (37 males and 37 females) aged between 18 to 50 years from the North Indian population. The MS area was measured using a NewTom CBCT machine (NewTom, Imola, Italy) with slicer software. The anatomical landmarks for the sinus were identified, and the area was calculated in square millimeters (mm2). RESULTS: In terms of surface area, females had a mean of 13,210.40 mm2 with a standard error of 713.46. Males, however, exhibited a higher mean surface area of 18,713.82 mm2, but with a significantly larger standard error of 3,371.70. The difference in MS area between males and females was statistically significant (p<0.01). In the receiver operating characteristic (ROC) curve, the area under the curve (AUC) was 0.77, suggesting good discriminative ability. CONCLUSION: The MS area on lateral cephalograms shows significant sexual dimorphism. Overall, the findings suggest that the MS surface area can be a useful anatomical feature for distinguishing between male and female North Indian subjects, given the statistically significant difference and the good discriminative performance indicated by the ROC curve analysis.

Sex chromosome turnover and biodiversity in fishes.

The impact of sex chromosomes and their turnover in speciation remains a subject of ongoing debate in the field of evolutionary biology. Fishes are the largest group of vertebrates, and they exhibit unparalleled sexual plasticity, as well as diverse sex-determining (SD) genes, sex chromosomes, and sex determination mechanisms. This diversity is hypothesized to be associated with the frequent turnover of sex chromosomes in fishes. Although it is evident that amh and amhr2 are repeatedly and independently recruited as SD genes, their relationship with the rapid turnover of sex chromosomes and the biodiversity of fishes remains unknown. We summarize the canonical models of sex chromosome turnover and highlight the vital roles of gene mutation and hybridization with empirical evidence. We revisit Haldane's rule and the large X-effect and propose the hypothesis that sex chromosomes accelerate speciation by multiplying genotypes via hybridization. By integrating recent findings on the turnover of SD genes, sex chromosomes, and sex determination systems in fish species, this review provides insights into the relationship between sex chromosome evolution and biodiversity in fishes.

No sex-dependent mortality in an amphibian upon infection with the chytrid fungus, Batrachochytrium dendrobatidis.

One of the major factors driving the currently ongoing biodiversity crisis is the anthropogenic spread of infectious diseases. Diseases can have conspicuous consequences, such as mass mortality events, but may also exert covert but similarly severe effects, such as sex ratio distortion via sex-biased mortality. Chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd) is among the most important threats to amphibian biodiversity. Yet, whether Bd infection can skew sex ratios in amphibians is currently unknown, although such a hidden effect may cause the already dwindling amphibian populations to collapse. To investigate this possibility, we collected common toad (Bufo bufo) tadpoles from a natural habitat in Hungary and continuously treated them until metamorphosis with sterile Bd culture medium (control), or a liquid culture of a Hungarian or a Spanish Bd isolate. Bd prevalence was high in animals that died during the experiment but was almost zero in individuals that survived until the end of the experiment. Both Bd treatments significantly reduced survival after metamorphosis, but we did not observe sex-dependent mortality in either treatment. However, a small number of genotypically female individuals developed male phenotype (testes) in the Spanish Bd isolate treatment. Therefore, future research is needed to ascertain if larval Bd infection can affect sex ratio in common toads through female-to-male sex reversal.

Gender Determination Through Mandibular Features on Orthopantomograms: A Preliminary Study.

Introduction Determination of gender can be highly accurate with a complete adult skeleton, but in scenarios like mass disasters, only fragmented bones might be available. In such cases, identifying gender relies significantly on which parts of the skeleton are found. The mandible is a notably distinct bone in the skull and can be key in determining gender, especially when the entire skull is not available. The mandibular features provide clues that can help forensic experts determine the gender of an individual. Aim of the study This preliminary study aimed to determine the gender of an individual using mandibular parameters such as coronoid ramus height, condylar ramus height, projective ramus, minimum ramus breadth, and maximum ramus breadth. The objectives of this study were to (i) determine the gender of an individual using various mandibular parameters, (ii) evaluate the effectiveness of these mandibular parameters in distinguishing between male and female individuals, and (iii) establish a reliable method for gender identification based on the measured mandibular parameters. Materials and methods Since it was a preliminary study, the sample size calculation was done using G*Power software (Version 3.1.9.4; Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany). The sample size was determined to guarantee a 95% statistical power at a significance level (alpha error probability) of 0.05. To ensure sufficient statistical power, a total of 100 samples were included, with a projected sample size of 92. A total of 100 samples, evenly split between 50 males and 50 females aged 20 to 30 years, were analyzed. Orthopantomograms (OPGs) showing pathologies, fractures, developmental disturbances of the mandible, and edentulous mandibles were excluded from the study. Statistical analysis was performed using SPSS for Windows, Version 16.0 (Released 2007; SPSS Inc., Chicago, IL, USA). Additionally, an accuracy test, analysis of variance (ANOVA), multiple regression, and discriminant analysis for gender were performed on individual data. Results In this study, five mandibular parameters were analyzed for gender such as coronoid ramus height, condylar ramus height, projective ramus, minimum ramus breadth, and maximum ramus breadth showed a positive correlation comparatively, and a novel formula was developed.  Conclusion According to the present study, panoramic radiography can be considered a valuable tool in sex determination (with an accuracy of 90%), and all parameters of the mandible exhibited sexual dimorphism, showing they are reliable parameters with a total accuracy of 90%. However, coronoid ramus height, projective ramus, and maximum ramus breadth played a significant role in identifying gender in this particular study.

Sex chromosome turnover plays an important role in the maintenance of barriers to post-speciation introgression in willows.

Almost all species in the genus Salix (willow) are dioecious and willows have variable sex-determining systems, the role of this variation in maintaining species barriers is relatively untested. We first analyzed the sex determination systems (SDS) of two species, Salix cardiophylla and Salix interior, whose positions in the Salix phylogeny make them important for understanding a sex chromosome turnover that has been detected in their relatives, and that changed the system from male (XX/XY) to female (ZW/ZZ) heterogamety. We show that both species have male heterogamety, with sex-linked regions (SLRs) on chromosome 15 (termed a 15XY system). The SLRs occupy 21.3% and 22.8% of the entire reference chromosome, respectively. By constructing phylogenetic trees, we determined the phylogenetic positions of all the species with known SDSs. Reconstruction of ancestral SDS character states revealed that the 15XY system is likely the ancestral state in willows. Turnovers of 15XY to 15ZW and 15XY to 7XY likely contributed to early speciation in Salix and gave rise to major groups of the Vetrix and Salix clades. Finally, we tested introgression among species in the phylogenetic trees based on both autosomes and SLRs separately. Frequent introgression was observed among species with 15XY, 15ZW, and 7XY on autosomes, in contrast to the SLR datasets, which showed less introgression, and in particular no gene flow between 15ZW and 7XY species. We argue that, although SDS turnovers in willow speciation may not create complete reproductive barriers, the evolution of SLRs plays important roles in preventing introgression and maintaining species boundaries.

Evidence for feminized genetic males in a flea beetle using newly identified X-linked markers.

The equilibrium of sex ratios in sexually reproducing species is often disrupted by various environmental and genetic factors, including endosymbionts like Wolbachia. In this study, we explore the highly female-biased sex ratio observed in the flea beetle, Altica lythri, and its underlying mechanisms. Ancient hybridization events between Altica species have led to mitochondrial DNA introgression, resulting in distinct mitochondrial haplotypes that go along with different Wolbachia infections (HT1-wLytA1, HT1*- uninfected, HT2-wLytA2, and HT3-wLytB). Notably, beetles with some haplotypes exclusively produce female offspring, suggesting potential Wolbachia-induced phenomena such as feminization of genetic males. However, the observed female bias could also be a consequence of the ancient hybridization resulting in nuclear-cytoplasmic conflicts between introgressed mtDNA and nuclear genes. Through transcriptomic analysis and the program SEX-DETector, we established markers for genotypic sex differentiation for A. lythri, enabling genetic sexing via qPCR. Our findings suggest that feminization of genetic males is contributing to the skewed sex ratios, highlighting the intricate dynamics of sex determination and reproductive strategies in this flea beetle. This study provides valuable insights into the dynamics of genetic conflicts, endosymbionts, and sex ratios, revealing the novel phenomenon of genetic male feminization in the flea beetle A. lythri.

Specificity of Key Sex Determination Genes in a Mammal with Ovotestes: The European Mole Talpa europaea.

Here, for the first time, the structure of genes involved in sex determination in mammals (full Sry and partial Rspo1, Eif2s3x, and Eif2s3y) was analyzed for the European mole Talpa europaea with ovotestes in females. We confirmed male-specificity for Eif2s3y and Sry. Five exons were revealed for Rspo1 and the deep similarity with the structure of this gene in T. occidentalis was proved. The most intriguing result was obtained for the Sry gene, which, in placental mammals, initiates male development. We described two exons for this canonically single-exon gene: the first (initial) exon is only 15 bp while the second exon includes 450 bp. The exons are divided by an extended intron of about 1894 bp, including the fragment of the LINE retroposon. Moreover, in chromatogram fragments, which correspond to intron and DNA areas, flanking both exons, we revealed double peaks, similar to heterozygous nucleotide sites of autosomal genes. This may indicate the existence of two or more copies of the Sry gene. Proof of copies requires an additional in-depth study. We hypothesize that unusual structure and possible supernumerary copies of Sry may be involved in ovotestes formation.

Development and validation of sex-linked molecular markers for rapid and accurate identification of male and female Hippophae tibetana plants.

Hippophae tibetana, one of the highest-altitude woody plants endemic to the Qinghai-Tibet Plateau, primarily thrives on riverbanks formed by glacial meltwater. As a dioecious species, it demonstrates significant ecological and economic value in extreme alpine environments. However, the lack of sex identification techniques outside of the flowering period severely limits research on sex ratio, differentiation, and breeding. There is an urgent need to develop effective sex-linked molecular markers that are independent of developmental stages, but current research in this area remains limited. This study developed a set of accurate sex-linked molecular markers for the rapid identification of male and female individuals of H. tibetana. Through whole-genome resequencing of 32 sexually differentiated H. tibetana samples, this study offers strong evidence supporting chromosome 2 as the sex chromosome and successfully identified key loci related to sex determination on this chromosome. Utilizing these loci, we, for the first time, developed three reliable pairs of sex-specific molecular markers, which exhibited high accuracy during validation across various geographic populations, offering an effective tool for the sex identification of H. tibetana. Additionally, this study lays the groundwork for further research into the mechanisms of sex determination and the evolution of sex chromosomes in H. tibetana.

Unravelling the novel sex determination genotype with 'ZY' and a distinctive 2.15-2.95 Mb inversion among poplar species through haplotype-resolved genome assembly and comparative genomics analysis.

Populus tomentosa, an indigenous tree species, is widely distributed and cultivated over 1,000,000 km2 in China, contributing significantly to forest production, ecological conservation and urban-rural greening. Although a reference genome is available for P. tomentosa, the intricate interspecific hybrid origins, chromosome structural variations (SVs) and sex determination mechanisms remain confusion and unclear due to its broad and even overlapping geographical distribution, extensive morphological variations and cross infiltration among white poplar species. We conducted a haplotype-resolved de novo assembly of P. tomentosa elite individual GM107, which comprises subgenomes a and b with a total genome size of 714.9 Mb. We then analysed the formation of hybrid species and the phylogenetic evolution and sex differentiation across the entire genus. Phylogenomic analyses suggested that GM107 likely originated from a hybridisation event between P. alba (♀) and P. davidiana (♂) approximately 3.8 Mya. A total of 1551 chromosome SVs were identified between the two subgenomes. More noteworthily, a distinctive inversion structure spanning 2.15-2.95 Mb was unveiled among Populus, Tacamahaca, Turaga, Aigeiros poplar species and Salix, highlighting a unique evolutionary feature. Intriguingly, a novel sex genotype of the ZY type, which represents a crossover between XY and ZW systems, was identified and confirmed through both natural and artificial hybrids populations. These novel insights offer significant theoretical value for the study of the species' evolutionary origins and serve as a valuable resource for ecological genetics and forest biotechnology.

Endoscopic techniques for early diagnosis of cloacal pathologies and sex determination in blue spotted tree monitor (Varanus macraei) and Cuming's water monitor (Varanus cumingi).

This article attempts to present, for the first time, the usefulness and feasibility of using endoscopic techniques in the cloacal region of Varanus cumingi and Varanus macraei. This method can serve both diagnostic and therapeutic purposes, as well as offering an early approach to sex determination through the observation of the urodeum which in males ends in a blind end while in females it consists of two ostia which represent the outlets of the oviducts. In this context, commonly employed sex determination techniques, such as post-cloacal spur detection, have shown unreliability. The study involved the examination of ten specimens, approximately one year old, from a private breeding farm, following a complete clinical evaluation to confirm their general state of health. All subjects underwent sedation, which allowed the evaluation of anatomical structures, the health status of the cloaca and the determination of sex. This study and its findings may provide a critical basis for addressing population declines of these species, particularly for V. macraei, which has already been classified as 'endangered' by the IUCN.

Loss of genetic variation and ancestral sex determination system in North American northern pike characterized by whole-genome resequencing.

The northern pike Esox lucius is a freshwater fish with low genetic diversity but ecological success throughout the Northern Hemisphere. Here we generate an annotated chromosome-level genome assembly of 941 Mbp in length with 25 chromosome-length scaffolds. We then genotype 47 northern pike from Alaska through New Jersey at a genome-wide scale and characterize a striking decrease in genetic diversity along the sampling range. Individuals west of the North American Continental Divide have substantially higher diversity than those to the east (e.g., Interior Alaska and St. Lawrence River have on average 181K and 64K heterozygous SNPs per individual, or a heterozygous SNP every 5.2 kbp and 14.6 kbp, respectively). Individuals clustered within each population with strong support, with numerous private alleles observed within each population. Evidence for recent population expansion was observed for a Manitoba hatchery and the St. Lawrence population (Tajima's D = -1.07 and -1.30, respectively). Several chromosomes have large regions with elevated diversity, including LG24, which holds amhby, the ancestral sex determining gene. As expected amhby was largely male-specific in Alaska and the Yukon and absent southeast to these populations, but we document some amhby(-) males in Alaska and amhby(+) males in the Columbia River, providing evidence for a patchwork of presence of this system in the western region. These results support the theory that northern pike recolonized North America from refugia in Alaska and expanded following deglaciation from west to east, with probable founder effects resulting in loss of both neutral and functional diversity (e.g., amhby).

Non-Mendelian transmission of X chromosomes: mechanisms and impact on sex ratios and population dynamics in different breeding systems.

The non-Mendelian transmission of sex chromosomes during gametogenesis carries significant implications, influencing sex ratios and shaping evolutionary dynamics. Here we focus on known mechanisms that drive non-Mendelian inheritance of X chromosomes during spermatogenesis and their impact on population dynamics in species with different breeding systems. In Drosophila and mice, X-linked drivers targeting Y-bearing sperm for elimination or limiting their fitness, tend to confer unfavourable effects, prompting the evolution of suppressors to mitigate their impact. This leads to a complex ongoing evolutionary arms race to maintain an equal balance of males and females. However, in certain insects and nematodes with XX/X0 sex determination, the preferential production of X-bearing sperm through atypical meiosis yields wild-type populations with highly skewed sex ratios, suggesting non-Mendelian transmission of the X may offer selective advantages in these species. Indeed, models suggest X-meiotic drivers could bolster population size and persistence under certain conditions, challenging the conventional view of their detrimental effects. Furthering our understanding of the diverse mechanisms and evolutionary consequences of non-Mendelian transmission of X chromosomes will provide insights into genetic inheritance, sex determination, and population dynamics, with implications for fundamental research and practical applications.

Evidence for NR2F2/COUP-TFII involvement in human testis development.

NR2F2 encodes COUP-TFII, an orphan nuclear receptor required for the development of the steroidogenic lineages of the murine fetal testes and ovaries. Pathogenic variants in human NR2F2 are associated with testis formation in 46,XX individuals, however, the function of COUP-TFII in the human testis is unknown. We report a de novo heterozygous variant in NR2F2 (c.737G > A, p.Arg246His) in a 46,XY under-masculinized boy with primary hypogonadism. The variant, located within the ligand-binding domain, is predicted to be highly damaging. In vitro studies indicated that the mutation does not impact the stability or subcellular localization of the protein. NR5A1, a related nuclear receptor that is a key factor in gonad formation and function, is known to physically interact with COUP-TFII to regulate gene expression. The mutant protein did not affect the physical interaction with NR5A1. However, in-vitro assays demonstrated that the mutant protein significantly loses the inhibitory effect on NR5A1-mediated activation of both the LHB and INSL3 promoters. The data support a role for COUP-TFII in human testis formation. Although mutually antagonistic sets of genes are known to regulate testis and ovarian pathways, we extend the list of genes, that together with NR5A1 and WT1, are associated with both 46,XX and 46,XY DSD.

Genomic Anatomy of Homozygous XX Females and YY Males Reveals Early Evolutionary Trajectory of Sex-determining Gene and Sex Chromosomes in Silurus Fishes.

Sex chromosomes display remarkable diversity and variability among vertebrates. Compared with research on the X/Y and Z/W chromosomes, which have long evolutionary histories in mammals and birds, studies on the sex chromosomes at early evolutionary stages are limited. Here, we precisely assembled the genomes of homozygous XX female and YY male Lanzhou catfish (Silurus lanzhouensis) derived from an artificial gynogenetic family and a self-fertilized family, respectively. Chromosome 24 (Chr24) was identified as the sex chromosome based on resequencing data. Comparative analysis of the X and Y chromosomes showed an approximate 320 kb Y-specific region with a Y-specific duplicate of anti-Mullerian hormone type II receptor (amhr2y), which is consistent with findings in 2 other Silurus species but on different chromosomes (Chr24 of Silurus meridionalis and Chr5 of Silurus asotus). Deficiency of amhr2y resulted in male-to-female sex reversal, indicating that amhr2y plays a male-determining role in S. lanzhouensis. Phylogenetic analysis and comparative genomics revealed that the common sex-determining gene amhr2y was initially translocated to Chr24 of the Silurus ancestor along with the expansion of transposable elements. Chr24 was maintained as the sex chromosome in S. meridionalis and S. lanzhouensis, whereas a sex-determining region transition triggered sex chromosome turnover from Chr24 to Chr5 in S. asotus. Additionally, gene duplication, translocation, and degeneration were observed in the Y-specific regions of Silurus species. These findings present a clear case for the early evolutionary trajectory of sex chromosomes, including sex-determining gene origin, repeat sequence expansion, gene gathering and degeneration in sex-determining region, and sex chromosome turnover.

Early fasting does not impact gonadal size nor vasa gene expression in the European seabass Dicentrarchus labrax.

Primordial germ cells (PGCs) play a crucial role in sexual development in fish, with recent studies revealing their influence on sexual fate. Notably, PGC number at specific developmental stages can determine whether an individual develops as male or female. Temperature was shown to impact PGC proliferation and the subsequent phenotypic sex in some fish species. Here, we aimed at testing the role of food deprivation on gonad development in the European seabass Dicentrarchus labrax, a species displaying a polygenic sex determination system with an environmental influence. We subjected larvae to two periods of starvation to investigate whether restricting growth affects both gonadal size and vasa gene expression. We first confirmed by immunohistochemistry that Vasa was indeed a marker of PGCs in the European seabass, as in other fish species. We also showed that vasa correlated positively with fish size, confirming that it could be used as a marker of feminization. However, starvation did not show any significant effects on vasa expression nor on gonadal size. It is hypothesized that evolutionary mechanisms likely safeguard PGCs against environmental stressors to ensure reproductive success. Further research is needed to elucidate the intricate interplay between environmental cues, PGC biology, and sexual differentiation in fish.

Determining Sex from Thai Radius: Discriminant Function Analysis Including the Dry Bone Weight as an Effective Variant

SUMMARY: In forensic anthropology, the radius bone has been shown to determine the sex of human remains in a number of different populations. The dry mass and growth of long bones, including the radius, are associated with sex hormone levels; however, the use of bone weight to determine sex has not been sufficiently investigated. The aim of this study was to apply bone morphometric parameters, including maximum length of radius (MLR), circumference at the midshaft of radius (CMR), and weight of radius (WR), to 400 sample radii from a Northeastern Thai population. Univariate and multivariate discriminant functions of all parameters were systemically applied. Equations for calculating sex classification were also determined. Descriptive data analysis showed significant sexual dimorphism in all variables (p < 0.05). The canonical correlation was highest in CMR (0.772) and the ratio of weight to length (0.747). Multivariate discriminant function analysis showed that the measured indices of the right radius were slightly greater than those of the left radius. The parameters demonstrating the highest values of the standardized canonical discriminant function coefficients were CMR (Rt. = 0.496, Lt. 0.431) and WR (Rt. = 0.681, Lt. = 0.715). Moreover, the results of the multivariable (stepwise method) indicated that the best accuracy rates for using combinations of CMR and WR were 94 % (right side) and 92 % (left side). In conclusion, the weight of the radius (rather than the length) is an effective parameter in determining sex.

En antropología forense, se ha demostrado que el hueso radio determina el sexo de los restos humanos en varias poblaciones diferentes. La masa seca y el crecimiento de los huesos largos, incluido el radio, están asociados con los niveles de hormonas sexuales; sin embargo, el uso del peso de los huesos para determinar el sexo no se ha investigado suficientemente. El objetivo de este estudio fue aplicar parámetros morfométricos óseos, incluida la longitud máxima del radio (LMR), la circunferencia en la mitad del radio (CMR) y el peso del radio (PR), a 400 radios de muestra de una población del noreste de Tailandia. Se aplicaron sistémicamente funciones discriminantes univariadas y multivariadas de todos los parámetros. También se determinaron ecuaciones para calcular la clasificación por sexo. El análisis descriptivo de los datos mostró un dimorfismo sexual significativo en todas las variables (p < 0,05). La correlación canónica fue mayor en CMR (0,772) y la relación peso-longitud (0,747). El análisis de función discriminante multivariante mostró que los índices del radio derecho eran ligeramente mayores que los del radio izquierdo. Los parámetros que demostraron los valores más altos de los coeficientes de la función discriminante canónica estandarizada fueron CMR (Rt. = 0,496, Lt. 0,431) y PR (Rt. = 0,681, Lt. = 0,715). Además, los resultados del método multivariable (método paso a paso) indicaron que las mejores tasas de precisión al usar combinaciones de CMR y PR fueron del 94 % (lado derecho) y del 92 % (lado izquierdo). En conclusión, el peso del radio (más que la longitud) es un parámetro eficaz para determinar el sexo.

Sex Determination from the Patella in a Thai Population / Determinación del Sexo a Partir de la Rótula en una Población Tailandesa

SUMMARY: The aim of this study was to derive the equations for sex determination and to test the accuracy of discrimination between sexes using measurements of the patella in the Thai population. The sample comprised 254 Thai skeletons (134 males and 120 females) aged between 22 and 97 years, with an average age of 63.3years, obtained from the Osteology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai. Six variables were measured in 254 pairs of normal patellae. The mean values of patellar measurements in males were significantly greater than those in females for all variables (P<0.05). Statistical analysis further showed that all variables were useful in sex determination. Stepwise discriminant function analysis yielded an accuracy of 83.2 % (83.8 % male, 82.5 % female) and 85.5 % (85.3 % male, 85.8 % female) for the left and right patellae, respectively. These results suggested that measurement of the right patella is preferable for skeletal sexing. If this is not available, the forensic specialist can use the left patella instead, with an average accuracy of more than 80.0 % in giving a correct classification. The findings of this study demonstrate that the patella is an important bone in sex determination. They suggest that either the left or right patella can be used for sex determination, especially in the Northern Thai population.

El objetivo de este estudio fue derivar las ecuaciones para la determinación del sexo y probar la precisión de la discriminación entre sexos utilizando mediciones de la patela en la población tailandesa. La muestra estuvo compuesta por 254 esqueletos tailandeses (134 hombres y 120 mujeres) con edades comprendidas entre 22 y 97 años, con una edad promedio de 63,3 años, del Centro de Investigación y Capacitación en Osteología de la Facultad de Medicina de la Universidad de Chiang Mai, Chiang Mai. Se midieron seis variables en 254 pares de patelas normales. Los valores medios de las mediciones patelares en los hombres fueron significativamente mayores que los de las mujeres, para todas las variables (P <0,05). Además, el análisis estadístico mostró que todas las variables fueron útiles para la determinación del sexo. El análisis de la función discriminante por pasos arrojó una precisión del 83,2 % (83,8 % hombres, 82,5 % mujeres) y 85,5 % (85,3 % hombres, 85,8 % mujeres) para las patelas izquierda y derecha, respectivamente. Estos resultados sugieren que la medición de la patela derecha es preferible para la determinación del sexo en esqueletos. En caso de no estar disponible y para dar una clasificación correcta, el especialista forense puede utilizar la patela izquierda, con una precisión promedio de más del 80,0 %. Los hallazgos de este estudio demuestran que la patela es un hueso importante en la determinación del sexo. Se sugiere que se pueda utilizar la patela izquierda o derecha para determinar el sexo, especialmente en la población del norte de Tailandia.