Displaying publications 1 - 20 of 133 in total

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  1. Walter KV, Conroy-Beam D, Buss DM, Asao K, Sorokowska A, Sorokowski P, et al.
    Psychol Sci, 2020 Apr;31(4):408-423.
    PMID: 32196435 DOI: 10.1177/0956797620904154
    Considerable research has examined human mate preferences across cultures, finding universal sex differences in preferences for attractiveness and resources as well as sources of systematic cultural variation. Two competing perspectives-an evolutionary psychological perspective and a biosocial role perspective-offer alternative explanations for these findings. However, the original data on which each perspective relies are decades old, and the literature is fraught with conflicting methods, analyses, results, and conclusions. Using a new 45-country sample (N = 14,399), we attempted to replicate classic studies and test both the evolutionary and biosocial role perspectives. Support for universal sex differences in preferences remains robust: Men, more than women, prefer attractive, young mates, and women, more than men, prefer older mates with financial prospects. Cross-culturally, both sexes have mates closer to their own ages as gender equality increases. Beyond age of partner, neither pathogen prevalence nor gender equality robustly predicted sex differences or preferences across countries.
    Matched MeSH terms: Sex Characteristics*
  2. Walter KV, Conroy-Beam D, Buss DM, Asao K, Sorokowska A, Sorokowski P, et al.
    Proc Biol Sci, 2021 Jul 28;288(1955):20211115.
    PMID: 34284630 DOI: 10.1098/rspb.2021.1115
    A wide range of literature connects sex ratio and mating behaviours in non-human animals. However, research examining sex ratio and human mating is limited in scope. Prior work has examined the relationship between sex ratio and desire for short-term, uncommitted mating as well as outcomes such as marriage and divorce rates. Less empirical attention has been directed towards the relationship between sex ratio and mate preferences, despite the importance of mate preferences in the human mating literature. To address this gap, we examined sex ratio's relationship to the variation in preferences for attractiveness, resources, kindness, intelligence and health in a long-term mate across 45 countries (n = 14 487). We predicted that mate preferences would vary according to relative power of choice on the mating market, with increased power derived from having relatively few competitors and numerous potential mates. We found that each sex tended to report more demanding preferences for attractiveness and resources where the opposite sex was abundant, compared to where the opposite sex was scarce. This pattern dovetails with those found for mating strategies in humans and mate preferences across species, highlighting the importance of sex ratio for understanding variation in human mate preferences.
    Matched MeSH terms: Sex Characteristics*
  3. Shapawi R, Anyie AL, Hussien MA, Zuldin WH
    Trop Life Sci Res, 2015 Dec;26(2):1-13.
    PMID: 26868706 MyJurnal
    Seahorse diversity (genus Hippocampus, Family Syngnathidae), species identification, size composition and sexual dimorphism were studied from November 2012 to March 2013 in selected coastal waters around Kota Kinabalu, Sabah and the local market trade. Six species of seahorses were identified in the study: (1) Hippocampus barbouri, (2) Hippocampus comes, (3) Hippocampus kelloggi, (4) Hippocampus kuda, (5) Hippocampus spinosissimus and (6) Hippocampus trimaculatus. All six species were sold at the local market, and the dried seahorses were obtained mainly by local fishermen using trawl by-catch method and traded as traditional medicine, souvenirs and other uses. Four species were identified by direct samplings in various different habitats of Kota Kinabalu coastal waters: (1) H. barbouri, (2) H. comes, (3) H. kuda, and (4) H. spinosissimus. Based on the results, H. comes was the largest in size among the four fresh/live species found (mean standard length [SL]: 148.25±1.26 mm), whereas H. barbouri was the smallest species (mean SL: 129±7.81 mm). For the dried samples, H. kelloggi was the largest (mean SL: 245.25±14.55 mm) and H. barbouri was the smallest (mean SL: 127.21±10.01 mm). No significant difference (p>0.05) was observed between the lengths of males and females in every seahorse species, and there was no sexual size dimorphism in any of the species. The findings from the study are significant to provide baseline data for the conservation efforts of these unique marine teleost.
    Matched MeSH terms: Sex Characteristics
  4. Mariana A, Santana Raj AS, Ho TM, Tan SN, Zuhaizam H
    Trop Biomed, 2008 Dec;25(3):217-24.
    PMID: 19287360
    Scanning electron microscope (SEM) images of two dust mites, Sturnophagoides brasiliensis and Sturnophagoides halterophilus, are presented to provide an improved visualization of the taxonomic characters of these mites. Sturnophagoides halterophilus can be differentiated from S. brasiliensis by their expanded genu and femur of leg I. The differences in morphology of male and female S. brasiliensis are also discussed.
    Matched MeSH terms: Sex Characteristics
  5. Hess SY, Zimmermann MB
    Eur. J. Endocrinol., 2000 Jun;142(6):599-603.
    PMID: 10822222
    The determination of goiter prevalence in children by thyroid ultrasound is an important tool for assessing iodine deficiency disorders. The current World Health Organization/International Council for the Control of Iodine Deficiency Disorders (WHO/ICCIDD) normative values, based on thyroid volume in iodine-sufficient European children, have recently been questioned, as thyroid volumes in iodine-sufficient children from the USA and Malaysia are smaller than the WHO/ICCIDD reference data. Our objective was to describe ultrasonographic thyroid volumes in a representative national sample of iodine-sufficient Swiss school children, and to compare these with the current reference data for thyroid volume.
    Matched MeSH terms: Sex Characteristics
  6. Tham LK, Osman NA, Lim KS, Pingguan-Murphy B, Abas WA, Zain NM
    Med Eng Phys, 2011 May;33(4):407-10.
    PMID: 21146440 DOI: 10.1016/j.medengphy.2010.11.002
    The investigation of patellar tendon reflex involves development of a reflex hammer holder, kinematic data collection and analysis of patellar reflex responses using motion analysis techniques. The main aim of this research is to explore alternative means of assessing reflexes as a part of routine clinical diagnosis. The motion analysis system was applied to provide quantitative data which is a more objective measure of the patellar tendon reflex. Kinematic data was collected from 28 males and 22 females whilst subjected to a knee jerk test. Further analysis of kinematic data was performed to predict relationships which might affect the patellar tendon reflex. All subjects were seated on a high stool with their legs hanging freely within the capture volume of the motion analysis system. Knee jerk tests were applied to all subjects, on both sides of the leg, by eliciting hypo, hyper, and normal reflexes. An additional reinforcement technique called the Jendrassik manoeuvre was also performed under the same conditions to elicit a normal patellar tendon reflex. The comparison of reflex response between genders showed that female subjects generally had a greater response compared to males. However, the difference in reflex response between the left leg and the right leg was not significant. Tapping strength to elicit a hyper-reflex produced greater knee-jerk compared to the normal clinical tapping strength. All results were in agreement with clinical findings and results found by some early researchers.
    Matched MeSH terms: Sex Characteristics
  7. Cheung TP, Van Rostenberghe H, Ismail R, Nawawi NN, Abdullah NA, Ramli N, et al.
    Gene, 2015 Dec 1;573(2):198-204.
    PMID: 26188155 DOI: 10.1016/j.gene.2015.07.045
    Constitutive androstane receptor (CAR) encoded by the nuclear receptor subfamily 1, group I, member 3 (NR1I3) gene regulates the elimination of bilirubin through activating the components of the bilirubin clearance pathway. Hence, NR1I3 genetic variants may affect bilirubin metabolism and result in neonatal hyperbilirubinemia. Thus far, research which investigates the association between NR1I3 variants and neonatal hyperbilirubinemia has not been undertaken in any population. The present study aimed to evaluate the influence of MPJ6_1I3008 (rs10157822), IVS8+116T>G (rs4073054) and 540A>G (rs2307424) on neonatal hyperbilirubinemia development in the Malay population. Buccal swabs were collected from 232 hyperbilirubinemia and 277 control term newborns with gestational age ≥37weeks and birth weight ≥2500g. The NR1I3 variants were genotyped by using high resolution melting (HRM) assays and verified by DNA sequencing. Gender, mode of delivery and birth weight did not differ between hyperbilirubinemia and control groups. The genotypic and allelic frequencies of MPJ6_1I3008, IVS8+116T>G and 540A>G were not significantly different between the groups. However, stratification by gender revealed a significant inverse association between homozygous variant genotype of MPJ6_1I3008 and risk of neonatal hyperbilirubinemia in the females (OR, 0.44; 95% CI, 0.20-0.95; p=0.034). This study demonstrates that the homozygous variant genotype of MPJ6_1I3008 was associated with a significant reduced risk of neonatal hyperbilirubinemia in the females.
    Matched MeSH terms: Sex Characteristics
  8. Liau KM, Yusof MI, Abdullah MS, Abdullah S, Yusof AH
    Spine (Phila Pa 1976), 2006 Jul 15;31(16):E545-50.
    PMID: 16845341
    A cross-sectional study of thoracic pedicle morphometry (T1-T12) of 180 Malaysian Malay patients obtained from computed tomographic scan.
    Matched MeSH terms: Sex Characteristics
  9. Chong CW, Wong LC, Teh CSJ, Ismail NH, Chan PQ, Lim CS, et al.
    J Food Biochem, 2020 12;44(12):e13535.
    PMID: 33103260 DOI: 10.1111/jfbc.13535
    Coffee is rich in antioxidant and has been shown to confer various health benefits. Here, we investigated the effect of single-dose coffee consumption in healthy human subjects. About 30 healthy volunteers were recruited and given a serving of sugar free black coffee. Urine and fecal samples were collected and analyzed. Significant changes in urinary metabolites relating to coffee, gut microbial and host energy metabolisms were observed post-coffee consumption. Clear sex differences were also observed in the urinary metabolic profiles pre- and post-coffee consumption. Sex differences in richness and composition of gut microbiota were observed, however, the effect of single-dose coffee consumption on host gut microbiota were unremarkable. These findings indicated that single-dose coffee consumption affects sex-specific host metabolic responses that relates to gut-microbe and energy metabolism. This study demonstrated the utility of systems biology tools to unravel complexity of host-diet biology and gut microbial responses. PRACTICAL APPLICATIONS: This study demonstrated that integrated systems biology approach enabled efficient extractions of host biochemical and microbial information that allows food industry to ascertain the impact of diet and longitudinal assessment of potential functional food in humans.
    Matched MeSH terms: Sex Characteristics
  10. Ismail N, Ohtsuka S, Maran BA, Tasumi S, Zaleha K, Yamashita H
    Parasite, 2013;20:42.
    PMID: 24165196 DOI: 10.1051/parasite/2013041
    The complete life cycle of a pennellid copepod Peniculus minuticaudae Shiino, 1956 is proposed based on the discovery of all post-embryonic stages together with the post-metamorphic adult females infecting the fins of threadsail filefish Stephanolepis cirrhifer (Monacanthidae) cultured in a fish farm at Ehime Prefecture, Japan. The hatching stage was the infective copepodid. The life cycle of P. minuticaudae consists of six stages separated by moults: the copepodid, four chalimi and adult. In this study, the adult males were observed frequently in precopulatory amplexus with various stages of females however, copulation occurs only between adults. Fertilized pre-metamorphic adult females carrying spermatophores may detach from the host and settle again before undergoing massive differential growth into the post-metamorphic adult female. Comparison of the life cycle of P. minuticaudae has been made with three known pennellids: Lernaeocera branchialis (Linnaeus, 1767), Cardiodectes medusaeus (Wilson, 1908) and Lernaeenicus sprattae (Sowerby, 1806). Among the compared species, P. minuticaudae is the first ectoparasitic pennellid to be discovered to complete its life cycle on a single host without any change in infection site preferences between infective copepodid and fertilized pre-metamorphic female.
    Matched MeSH terms: Sex Characteristics
  11. Thomas AG, Harrison S, Mogilski JK, Stewart-Williams S, Workman L
    Arch Sex Behav, 2024 Feb;53(2):611-627.
    PMID: 38030825 DOI: 10.1007/s10508-023-02749-6
    Polygamy is a form of "one-sided" consensually non-monogamous relationship where one person has multiple committed partners, each of whom is only involved with that one person. It was likely a reoccurring feature of ancestral mating that posed adaptive problems for our ancestors. Yet polygamy, and multi-partnering more generally, is understudied in Western cultures, raising questions about the existence of polygamous interest and whether this is calibrated adaptively to personal conditions. In two studies, we examined polygamous interest in two heterosexual online samples from the UK. In Study 1 (N = 393), modest interest was found for polygamous relationships overall. Men were six times more open to polygyny than women, but there was little sex difference in openness to polyandry. Further analysis revealed that all forms of multi-partnering were undesirable relative to singlehood and monogamy; however, consensual multi-partner relationships were less undesirable than non-consensual ones. Sex differences were largest for polygyny and arrangements where men had agreed access to a casual partner alongside a committed one, yet these were two of the most acceptable forms of multi-partnering when men and women's responses were combined. Sociosexuality positively predicted interest in most forms of multi-partnering. Study 2 (N = 735) focused on polygyny and added status-linked traits as predictors. The results of Study 1 were broadly replicated, though the status-linked traits did not predict polygynous interest specifically. Instead, sociosexuality and male intrasexual competitiveness uniquely predicted general interest in multi-partner relationships. Overall, interest in polygamy appears to emerge despite social discouragement and sex differences in interest track the relative costs and benefits associated with it. However, there is no strong evidence that polygamous interest is uniquely calibrated to personal conditions when compared to other forms of multi-partnering.
    Matched MeSH terms: Sex Characteristics
  12. Gholami SK, Tay CS, Lee JM, Zagoren E, Maris SA, Wong JY, et al.
    J Endocrinol, 2021 11 24;252(1):1-13.
    PMID: 34643545 DOI: 10.1530/JOE-21-0126
    Inconsistencies have been reported on the effect of sex on aldosterone (ALDO) levels leading to clinical confusion. The reasons for these inconsistencies are uncertain but include estrogen and/or its receptor modulating target gene responses to mineralocorticoid receptor activation and ALDO secretagogues' levels. This study's goal was to determine whether ALDO's biosynthesis also differed by sex. Two approaches were used. First, plasma renin activity and aldosterone were measured in rats. Both were significantly higher in males. Secondly, using rat zona glomerulosa (ZG) cells, we assessed three ex vivo areas: (1) activity/levels of early steps in ALDO's biosynthesis (StAR and CYP11A1); (2) activity/levels of a late step (CYP11B2); and (3) the status of the mineralocorticoid receptor (MR)-mediated, ultrashort feedback loop. Females had higher expression of CYP11A1 and StAR and increased CYP11A1 activity (increased pregnenolone/corticosterone levels) but did not differ in CYP11B2 expression or activity (ALDO levels). Activating the ZG's MR (thereby activating the ultrashort feedback loop) reduced CYP11B2's activity similarly in both sexes. Exvivo, these molecular effects were accompanied, in females, by lower ALDO basally but higher ALDO with angiotensin II stimulation. In conclusion, we documented that not only was there a sex-mediated difference in the activity of ALDO's biosynthesis but also these differences at the molecular level help explain the variable reports on ALDO's circulating levels. Basally, both in vivo and ex vivo, males had higher ALDO levels, likely secondary to higher ALDO secretagogue levels. However, in response to acute stimulation, ALDO levels are higher in females because of the greater levels and/or activity of their StAR/CYP11A1.
    Matched MeSH terms: Sex Characteristics*
  13. Li T, Pappas C, Le ST, Wang Q, Klinedinst BS, Larsen BA, et al.
    Neurobiol Aging, 2022 Jan;109:158-165.
    PMID: 34740077 DOI: 10.1016/j.neurobiolaging.2021.09.020
    The Apolipoprotein E ε4 (APOE ε4) haplotype is the strongest genetic risk factor for late-onset Alzheimer's disease (AD). The Translocase of Outer Mitochondrial Membrane-40 (TOMM40) gene maintains cellular bioenergetics, which is disrupted in AD. TOMM40 rs2075650 ('650) G versus A carriage is consistently related to neural and cognitive outcomes, but it is unclear if and how it interacts with APOE. We examined 21 orthogonal neural networks among 8,222 middle-aged to aged participants in the UK Biobank cohort. ANOVA and multiple linear regression tested main effects and interactions with APOE and TOMM40 '650 genotypes, and if age and sex acted as moderators. APOE ε4 was associated with less strength in multiple networks, while '650 G versus A carriage was related to more language comprehension network strength. In APOE ε4 carriers, '650 G-carriage led to less network strength with increasing age, while in non-G-carriers this was only seen in women but not men. TOMM40 may shift what happens to network activity in aging APOE ε4 carriers depending on sex.
    Matched MeSH terms: Sex Characteristics*
  14. Dalu T, Wasserman RJ, Vink TJ, Weyl OL
    Sci Rep, 2017 02 24;7:43229.
    PMID: 28233858 DOI: 10.1038/srep43229
    It is generally accepted that organisms that naturally exploit an ecosystem facilitate coexistence, at least partially, through resource partitioning. Resource availability is, however, highly variable in space and time and as such the extent of resource partitioning must be somewhat dependent on availability. Here we test aspects of resource partitioning at the inter- and intra-specific level, in relation to resource availability in an atypical aquatic environment using an isotope approach. Using closely related key organisms from an ephemeral pond, we test for differences in isotopic signatures between two species of copepod and between sexes within each species, in relation to heterogeneity of basal food resources over the course of the ponds hydroperiod. We show that basal food resource heterogeneity increases over time initially, and then decreases towards the end of the hydroperiod, reflective of the expected evolution of trophic complexity for these systems. Resource partitioning also varied between species and sexes, over the hydroperiod with intra- and inter-specific specialisation relating to resource availability. Intra-specific specialisation was particularly evident in the omnivorous copepod species. Our findings imply that trophic specialisation at both the intra- and inter-specific level is partly driven by basal food resource availability.
    Matched MeSH terms: Sex Characteristics*
  15. Alam MK, Mohd Noor NF, Basri R, Yew TF, Wen TH
    PLoS One, 2015;10(11):e0142914.
    PMID: 26562655 DOI: 10.1371/journal.pone.0142914
    This study aimed to investigate the association of facial proportion and its relation to the golden ratio with the evaluation of facial appearance among Malaysian population. This was a cross-sectional study with 286 randomly selected from Universiti Sains Malaysia (USM) Health Campus students (150 females and 136 males; 100 Malaysian Chinese, 100 Malaysian Malay and 86 Malaysian Indian), with the mean age of 21.54 ± 1.56 (Age range, 18-25). Facial indices obtained from direct facial measurements were used for the classification of facial shape into short, ideal and long. A validated structured questionnaire was used to assess subjects' evaluation of their own facial appearance. The mean facial indices of Malaysian Indian (MI), Malaysian Chinese (MC) and Malaysian Malay (MM) were 1.59 ± 0.19, 1.57 ± 0.25 and 1.54 ± 0.23 respectively. Only MC showed significant sexual dimorphism in facial index (P = 0.047; P<0.05) but no significant difference was found between races. Out of the 286 subjects, 49 (17.1%) were of ideal facial shape, 156 (54.5%) short and 81 (28.3%) long. The facial evaluation questionnaire showed that MC had the lowest satisfaction with mean score of 2.18 ± 0.97 for overall impression and 2.15 ± 1.04 for facial parts, compared to MM and MI, with mean score of 1.80 ± 0.97 and 1.64 ± 0.74 respectively for overall impression; 1.75 ± 0.95 and 1.70 ± 0.83 respectively for facial parts.
    Matched MeSH terms: Sex Characteristics
  16. Beaucournu JC, Wells K
    Parasite, 2005 Sep;12(3):237-40.
    PMID: 16218211
    This species, known only by a single male, is described from Mount Kinabalu and thus is recorded from the same area as Macrostylophora borneensis (Jordan, 1926), teste Traub (1972). It is distinguished from its congeneric and characterized by the absence of eriged setae on the thorax and first abdominal tergits, as well as by the shape of terminal segments and the phallosom. Macrostylophora kinabaluae was found to parasitize the Sciurid rodent Callosciurus prevostii that is widespread throughout most areas in the Malaysian subregion.
    Matched MeSH terms: Sex Characteristics
  17. Singh D, Narayanan S, Shanmugam T, Vicknasingam B
    J Psychoactive Drugs, 2021 Mar 22.
    PMID: 33749541 DOI: 10.1080/02791072.2021.1900627
    People who use amphetamine-type stimulant (ATS) are known to face barriers in seeking treatment. We sought to identify these barriers and gender differences in barriers (if any) faced by them. A convenience sample of 386 respondents who use ATS was recruited from five formal drug rehabilitation centers for this cross-sectional study. The majority were male (83%), with 17% being female. The barriers most frequently cited by both men and women were: the perception that ATS use needed no treatment, fears of community discrimination, peer influence, and long waiting time to get into a treatment programme. One-third of the sample held that the mandated treatment programmes were ineffective, based on past experience. In terms of male-female differences, long waiting time discouraged significantly more women than men, whereas more men than women asserted that formal treatment programmes were ineffective. We also found no significant differences in barriers faced by ATS users and those using ATS with other illicit substances. Outreach initiatives to minimize the impact of treatment barriers, coupled with offering separate treatment protocols and facilities, will encourage people who use ATS to seek treatment voluntarily.
    Matched MeSH terms: Sex Characteristics
  18. Hwong WY, Bots ML, Selvarajah S, Sivasampu S, Reidpath DD, Law WC, et al.
    Int J Stroke, 2019 10;14(8):826-834.
    PMID: 30843480 DOI: 10.1177/1747493019832995
    BACKGROUND: Sex differences in cardiovascular diseases generally disadvantage women, particularly within developing regions.

    AIMS: This study aims to examine sex-related differences in stroke metrics across Southeast Asia in 2015. Furthermore, relative changes between sexes are compared from 1990 to 2015.

    METHODS: Data were sourced from the Global Burden of Disease Study. Incidence and mortality from ischemic and hemorrhagic strokes were explored with the following statistics derived: (1) women-to-men incidence/mortality ratio and (2) relative percentage change in rate.

    RESULTS: Women had lower incidence and mortality from stroke compared to men. Notable findings include higher ischemic stroke incidence for women at 30-34 years in high-income countries (women-to-men ratio: 1.3, 95% CI: 0.1, 16.2 in Brunei and 1.3, 95% CI: 0.5, 3.2 in Singapore) and the largest difference between sexes for ischemic stroke mortality in Vietnam and Myanmar across most ages. Within the last 25 years, greater reductions for ischemic stroke metrics were observed among women compared to men. Nevertheless, women below 40 years in some countries showed an increase in ischemic stroke incidence between 0.5% and 11.4%, whereas in men, a decline from -4.2% to -44.2%. Indonesia reported the largest difference between sexes for ischemic stroke mortality; a reduction for women whereas an increase in men. For hemorrhagic stroke, findings were similar: higher incidence among young women in high-income countries and greater reductions for stroke metrics in women than men over the last 25 years.

    CONCLUSIONS: Distinct sex-specific differences observed across Southeast Asia should be accounted in future stroke preventive guidelines.

    Matched MeSH terms: Sex Characteristics*
  19. Khamis MF, Taylor JA, Malik SN, Townsend GC
    Forensic Sci Int, 2014 Jan;234:183.e1-7.
    PMID: 24128748 DOI: 10.1016/j.forsciint.2013.09.019
    Information about the sex of individuals is important for human identification. This study was conducted to quantify classification rates of sex prediction models for Malaysians using odontometric profiles. Mesiodistal (MD) and buccolingual (BL) crown dimensions of the permanent dentition were studied in 400 young adult Malaysians, giving a total of 28 tooth size variables. The sample consisted of three major ethnic groups, the Malays, Chinese and Tamils, since the aim was to assess sex dimorphism in Malaysians as a whole. Results showed that the mesiodistal diameter of the lower canine was the most sexually dimorphic dimension in Malaysian Malays and Tamils. Univariate analyses showed that the magnitude and pattern of sex dimorphism varies between these three ethnic groups, with Malaysian Chinese and Tamils being more dimorphic than the Malaysian Malays. Stepwise discriminant functions were generated bearing in mind their application in practical forensic situations. The range of classification rates was from 70.2% to 78.5% for the composite Malaysian group, and 83.8%, 77.9%, 72.4% for Malaysian Chinese, Malays and Tamils, respectively. The 'Area Under the Receiver Operating Characteristic Curve statistics' indicated good classification rates for three prediction models obtained using a combination of all tooth size variables, mandibular teeth, and mesiodistal dimensions in the composite Malaysian group, and for all tooth size variables in each ethnic group. The present study provides strong support for the value of odontometry as an adjunct scientific method for sex prediction in human identification.
    Matched MeSH terms: Sex Characteristics*
  20. Mihailidis S, Scriven G, Khamis M, Townsend G
    Am. J. Phys. Anthropol., 2013 Sep;152(1):19-30.
    PMID: 23913636 DOI: 10.1002/ajpa.22323
    We present new data on the prevalence and patterning of the maxillary premolar accessory ridge (MxPAR), a common but understudied morphological dental trait that is expressed as a linear elevation extending from the buccal cusp ridge to the medial sulcus of maxillary premolar teeth. A total of 579 sets of dental casts, representing six ethnic groups, were scored using the five-grade system proposed by Burnett et al. (2010). The frequency and distribution of the MxPAR were determined by tooth type, sex, side, locus and ethnicity, and the applicability of the scoring system was assessed. The MxPAR was found in approximately two-thirds of premolar teeth, more often on second than first premolars, and more often on the distal aspect of the occlusal surface than the mesial. There was some evidence that more pronounced forms of the feature occurred more often in males than females, and that there may be some directionality in its expression between sides. Variation was also noted in the frequency of occurrence and degree of expression of the MxPAR between ethnic groups. Intra- and inter-observer concordance rates for scoring the MxPAR were low, confirming that it was difficult to score the trait identically on two different occasions. Our findings have clarified the distribution of the MxPAR within the dentition and between ethnic groups, and highlighted the need for researchers to carry out thorough replicability studies and to decide on an appropriate breakpoint for determining presence or absence of this feature before embarking on genetic studies or bio-distance analyses.
    Matched MeSH terms: Sex Characteristics
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