Dimorphic Pattern Research Articles

Measuring the repertoire of age-related behavioral changes in Drosophila melanogaster.

Aging affects almost all aspects of an organism—its morphology, its physiology, its behavior. Isolating which biological mechanisms are regulating these changes, however, has proven difficult, potentially due to our inability to characterize the full repertoire of an animal’s behavior across the lifespan. Using data from fruit flies (D. melanogaster) we measure the full repertoire of behaviors as a function of age. We observe a sexually dimorphic pattern of changes in the behavioral repertoire during aging. Although the stereotypy of the behaviors and the complexity of the repertoire overall remains relatively unchanged, we find evidence that the observed alterations in behavior can be explained by changing the fly’s overall energy budget, suggesting potential connections between metabolism, aging, and behavior.

Loss of Nobox prevents ovarian differentiation from juvenile ovaries in zebrafish.

As a species without master sex-determining genes, zebrafish displays high plasticity in sex differentiation, making it an excellent model for studying the regulatory mechanisms underlying gonadal differentiation and gametogenesis. Despite being a gonochorist, zebrafish is a juvenile hermaphrodite that undergoes a special phase of juvenile ovary before further differentiation into functional testis and ovary. The mechanisms underlying juvenile ovary formation and subsequent gonadal differentiation remain largely unknown. In this study, we explored the role of Nobox/nobox (new born ovary homeobox protein), another oocyte-specific transcription factor in females, in early zebrafish gonadogenesis using CRISPR/Cas9 technology. As in mammals, nobox is specifically expressed in zebrafish gonads with a dimorphic pattern at juvenile stage. In contrast to the mutant of figla (factor in the germline alpha, another oocyte-specific transcription factor), the nobox mutants showed formation of typical perinucleolar (PN) follicles at primary growth (PG) stage in juvenile gonads, suggesting occurrence of follicle assembly from cystic oocytes (chromatin nucleolar stage, CN). These follicles, however, failed to develop further to form functional ovaries, resulting in all-male phenotype. Despite its expression in adult testis, the loss of nobox did not seem to affect testis development, spermatogenesis and male spawning. In summary, our results indicate an important role for Nobox in zebrafish ovarian differentiation and early folliculogenesis.

TCDD aggravates the formation of the atherosclerotic plaque in ApoE KO mice with a sexual dimorphic pattern

Aryl hydrocarbon receptor (AhR) ligands are recognized as aggravating factors in cardiovascular diseases but little is known about the role of the AhR in atherosclerosis considering the effects of age and gender. We exposed male and female ApoE knock-out mice, a model to study the pathogenesis of atherosclerosis, to a potent AhR ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) by an intraperitoneal injection of 1 μg/kg/week for 8 weeks. Atherosclerotic lesions, histological parameters and critical atherosclerotic markers in aorta were analysed. TCDD increased atherogenic lesions in 35-week old female mice, leading to a switch of vascular smooth muscle cells (VSMCs) from a contractile to a pro-atherogenic phenotype and increased expression for VCAM1. AhR activation accelerates the formation of atherosclerotic plaques with sex and age differences due to the phenotypical switch of VSMCs.

Variation in size and shape sexual dimorphism in the Sceloporus scalaris species group (Squamata: Phrynosomatidae) from the Transvolcanic Belt of Mexico

Abstract We attempted to identify the factors influencing size and shape dimorphism between sexes, as well as among populations and species in the Sceloporus scalaris group (Sceloporus aeneus, S. scalaris, S. bicanthalis and S. subniger). Our analysis focused on five morphological characteristics: snout–vent length, head length, head width, forearm length and tibia length. The effect of environmental variables (precipitation and temperature) on these variables was also tested. We found differences in morphological traits between sexes, and among populations of the same species. The oviparous species (S. aeneus and S. scalaris) were larger in overall body size than the viviparous species (S. bicanthalis and S. subniger). Differences in overall body size among populations were recorded only in S. aeneus and S. scalaris. Male-biased sexual size dimorphism occurred in oviparous but not viviparous lizards (except for one population of S. bicanthalis). An absence of sexual size dimorphism was also recorded in S. subniger and some populations of the remaining species. Two different shape patterns were found; the first was female-biased with larger relative body length in almost all populations, which could be explained by fecundity, and the second was male-biased with relatively larger head and limbs in a few populations, which may be explained by sexual selection. The patterns of sexual size and shape dimorphism show that environment, rather than phylogeny, may be determining the extent of sexual dimorphism. These types of studies show the importance of an integrated evaluation of interpopulation and interspecies variation to determine the factors that generate sexual dimorphism.

Association Study between DUF1220 Copy Number and Severity of Social Impairment in Sex-balanced Simplex Cases of Autism.

Copy number variations (CNVs), which are genetic factors responsible for human evolution, have emerged as underlying pathogenic factors for a number of diseases such as autism spectrum disorders (ASD). DUF1220 coding sequences have been shown to be positively associated with the severity of symptoms in familial/multiplex cases of autism. However, this association has not been confirmed in simplex autism, and the potential impact of gender/sex has not been studied. Using saliva samples taken from Iranian children with non-syndromic simplex autism, different ethnicity/race and genetic backgrounds from previous studies, we assessed the association between DUF1220 CNVs and Autism Diagnostic Interview-Revised (ADI-R) domain scores in both males and females. In the male and female combined group with autism, in line with previous reports, our findings showed that there were no significant associations between DUF1220 CNVs with either total ADI-R score, social, communication, or repetitive diagnostic scores in simplex autism cases. Interestingly, however, in sex classified groups, despite the insignificant results, our findings in girls with autism showed a negative trend between DUF1220 CNVs and severity of symptoms for the social interaction and communication domains. By contrast, in male children with autism, the results showed a positive trend. It seems that association of DUF1220 CNV with the severity of symptoms in simplex children with autism may follow a sexually dimorphic pattern that needs to be re-examined in prospective studies.

General patterns of sexual dimorphism in graylings (Thymallus), with a comparison to other salmonid species

Among fishes, salmonids (family Salmonidae) have attracted a great deal of research attention focused on sexual dimorphism and associated selective forces. Most of this research has been directed toward anadromous and mostly semelparous salmon and trout (Oncorhynchus, Salmo), and comparatively little is known about intersexual variability in strictly iteroparous freshwater salmonids. We examined a comprehensive data set of 28 linear morphometric characters in 11 of 15 currently recognised species of grayling (Thymallinae, Thymallus), a genus consisting of iteroparous species only, to identify general patterns of intersexual morphological variability. Overall, we found that all grayling species show common sex-specific traits particularly relating to size dimensions of the dorsal, anal, pelvic and pectoral fins. Although the magnitude of sexual dimorphism differed among species, there was no significant phylogenetic signal associated with these differences across the genus. These results are discussed in terms of the assumed selection pressures driving sexual dimorphism in graylings and are compared to existing knowledge in Salmonidae as a whole where similarities and differences with both Salmoninae and Coregoninae exist. The present study provides the first detailed genus-wide comparison of sexually dimorphic phenotypic characters in graylings, and highlights the need for more large-scale comparative studies in multiple salmonid species to better understand general macroevolutionary trends among this important group of freshwater fishes.

Temporal and Quantitative Transcriptomic Differences Define Sexual Dimorphism in Murine Postnatal Bone Aging.

ABSTRACTTime is a central element of the sexual dimorphic patterns of development, pathology, and aging of the skeleton. Because the transcriptome is a representation of the phenome, we hypothesized that both sex and sex‐specific temporal, transcriptomic differences in bone tissues over an 18‐month period would be informative to the underlying molecular processes that lead to postnatal sexual dimorphism. Regardless of age, sex‐associated changes of the whole bone transcriptomes were primarily associated not only with bone but also vascular and connective tissue ontologies. A pattern‐based approach used to screen the entire Gene Expression Omnibus (GEO) database against those that were sex‐specific in bone identified two coordinately regulated gene sets: one related to high phosphate–induced aortic calcification and one induced by mechanical stimulation in bone. Temporal clustering of the transcriptome identified two skeletal tissue‐associated, sex‐specific patterns of gene expression. One set of genes, associated with skeletal patterning and morphology, showed peak expression earlier in females. The second set of genes, associated with coupled remodeling, had quantitatively higher expression in females and exhibited a broad peak between 3 to 12 months, concurrent with the animals' reproductive period. Results of phenome‐level structural assessments of the tibia and vertebrae, and in vivo and in vitro analysis of cells having osteogenic potential, were consistent with the existence of functionally unique, skeletogenic cell populations that are separately responsible for appositional growth and intramedullary functions. These data suggest that skeletal sexual dimorphism arises through sex‐specific, temporally different processes controlling morphometric growth and later coupled remodeling of the skeleton during the reproductive period of the animal. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

A novel key driver gene of Alzheimer's disease impacts AD-related cognitive deficit, pathology and neuro-inflammation in sex- and APOE-specific manners.

Alzheimer's Disease (AD) has complex etiologies and the impact of sex on AD varies over the course of disease development. Literature provides some evidence of sex-specific contributions to AD. However, molecular mechanisms of sex biased differences in AD remain elusive. Multi-omics data in tandem with systems biology approaches offer a new avenue to not only dissect sex-stratified molecular mechanisms of AD but also develop sex-specific diagnostic and therapeutic strategies for AD. We integrated RNA expression datasets from the para-hippocampal gyrus of the Mount Sinai Medical Center Brain Bank (MSBB) and the prefrontal cortex from the Religious Orders Study and Rush Memory and Aging Project (ROSMAP) to perform multiscale network analysis. The differentially expressed genes (DEGs) between AD and control, female and male, ApoE3 and ApoE4 genotype were rank-ordered based on their relevance to clinical dementia rating scale (CDR) and AD pathology (Braak stage, CERAD and plaque density). The trend analyses and gene co-expression network analysis were then performed to identify key drivers with sexually dimorphic expression patterns or differentially respond to APOE genotypes between sexes. In this study, we identified ldl receptor-related protein (lrp10), a receptor possibly involved in the uptake of ApoE and APP trafficking as the highest-ranked key driver gene candidate accounting for the sex differences in AD. Lrp10 mRNA was increased in female AD patients when compared to female controls or male AD patients. In contrast, LRP10 protein levels were reduced in AD when compared to controls, suggesting possible post-translational modifications of LRP10 in AD human brains. Gene perturbation studies in EFAD mouse hippocampal brain regions suggest that over-expression of lrp10 improved cognitive function, reduced Aβ42 and p-Tau, and increased microglial recruitment around amyloid plaques in female E4FAD mice. In contrast, down-regulation of lrp10 exacerbated cognitive impairment as well as increased brain Aβ42 and total tau levels in male E3FAD mice. These results strongly support our hypothesis that lrp10 is a causal regulator gene for AD, whose expression is strongly associated with cognition performance in sex- and APOE-specific manners. Our findings further implicate a role of lrp10 in regulating microglial function and neuro-inflammation in AD.

Identification and Characterization of Dimorphic Expression of Sex-Related Genes in Rock Bream, a Fish With Multiple Sex Chromosomes.

The rock bream (Oplegnathus fasciatus) is a typical fish with a unique multiple sex chromosome system. In this study, we investigated the gene expression profiling in the gonads and brains of both males and females using RNA-Seq to identify sex-related genes and pathways. In accordance with the dimorphic expression profiles, combined with Gene ontology and KEGG enrichment analyses, a number of potential genes and pathways associated with sex determination were obtained from transcriptional analysis, especially some sex-biased genes and pathways. Next, we selected 18 candidate genes and analyzed their expression in different tissues and developmental stages. We found that the expression levels of Amh, Dmrt1, Sox9, Dmrtb1, and Nanos2 were significantly higher in the testis than those in the ovary or other tissues, whereas the expression levels of ZP4, Bouncer, RNF208, FoxH1, and TOB were significantly higher in the ovary than those in the testis. Furthermore, the expression levels of these genes in different developmental stages of gonads also showed sexually dimorphic patterns, suggesting that they might play important roles during gonadal development. These genes are useful markers for investigating sex determination and differentiation in rock bream. The findings of this study can provide insights into the molecular mechanisms of sex determination and differentiation in fish with multiple sex chromosome systems.

Sexually dimorphic patterns in maternal circulating microRNAs in pregnancies complicated by fetal growth restriction

BackgroundCurrent methods fail to accurately predict women at greatest risk of developing fetal growth restriction (FGR) or related adverse outcomes, including stillbirth. Sexual dimorphism in these adverse pregnancy outcomes is well documented as are sex-specific differences in gene and protein expression in the placenta. Circulating maternal serum microRNAs (miRNAs) offer potential as biomarkers that may also be informative of underlying pathology. We hypothesised that FGR would be associated with an altered miRNA profile and would differ depending on fetal sex.MethodsmiRNA expression profiles were assessed in maternal serum (> 36 weeks’ gestation) from women delivering a severely FGR infant (defined as an individualised birthweight centile (IBC) < 3rd) and matched control participants (AGA; IBC = 20–80th), using miRNA arrays. qPCR was performed using specific miRNA primers in an expanded cohort of patients with IBC < 5th (n = 15 males, n = 16 females/group). Maternal serum human placental lactogen (hPL) was used as a proxy to determine if serum miRNAs were related to placental dysfunction. In silico analyses were performed to predict the potential functions of altered miRNAs.ResultsInitial analyses revealed 11 miRNAs were altered in maternal serum from FGR pregnancies. In silico analyses revealed all 11 altered miRNAs were located in a network of genes that regulate placental function. Subsequent analysis demonstrated four miRNAs showed sexually dimorphic patterns. miR-28-5p was reduced in FGR pregnancies (p < 0.01) only when there was a female offspring and miR-301a-3p was only reduced in FGR pregnancies with a male fetus (p < 0.05). miR-454-3p was decreased in FGR pregnancies (p < 0.05) regardless of fetal sex but was only positively correlated to hPL when the fetus was female. Conversely, miR-29c-3p was correlated to maternal hPL only when the fetus was male. Target genes for sexually dimorphic miRNAs reveal potential functional roles in the placenta including angiogenesis, placental growth, nutrient transport and apoptosis.ConclusionsThese studies have identified sexually dimorphic patterns for miRNAs in maternal serum in FGR. These miRNAs may have potential as non-invasive biomarkers for FGR and associated placental dysfunction. Further studies to determine if these miRNAs have potential functional roles in the placenta may provide greater understanding of the pathogenesis of placental dysfunction and the differing susceptibility of male and female fetuses to adverse in utero conditions.

Sexual dimorphism and static allometry in the South African scorpion Opistophthalmus karrooensis

Sexual dimorphism in scorpions is generally retrieved for a similar subset of body parts and is presumed to result from alternative types of selection operating on homologous structures in each sex. Even so, investigations which use static allometry as a method for testing specific hypotheses relating to selection remain limited. Sexual dimorphism in the majority of South African scorpion species is poorly investigated, especially in the genus Opistophthalmus, of which the endemic Karoo burrowing scorpion O. karrooensis is nearly completely data deficient. The current study investigates patterns of sexual dimorphism and static allometry in O. karrooensis, based on external morphology. Following character scaling on carapace length, patterns of sexual dimorphism in this species indicate the elongation of male appendages (pedipalp segments, legs, pectines, metasoma, and telson), while females display wider bodies and wide, thick pedipalp segments. These patterns possibly point to an enhanced reproductive output and parental care in females, coupled to a sedentary lifestyle and generalist feeding strategy. Conversely, the male morphology is likely adapted for greater vagility, but should also function during mate-trailing and sexual interactions. In line with these explanations, the body parts in both sexes indicate static allometric patterns pointing (at least in part) to the potential influence of either natural or sexual selection, but further reveal the possibility of intense selection on a number of body parts. Taken together, the selective forces which shape scorpion morphology may be complex, relating to multiple functions of body parts and life-history differences between the sexes.

Metric sexual dimorphism of the skull in Thailand

The increasing recognition in forensic anthropology of variation in sexual dimorphism of skull size and shape among and within human populations has increased motivation among researchers to collect craniometric data from regional populations. Modern high levels of migration on an international scale has contributed to this endeavour, as has increasing understanding of historic population histories across the world. Mainland Southeast Asia is a region that has a complex population history. A large sample of male and female skulls (n = 322) selected from a collection of donated modern skeletons from northeast Thailand is used in this study to provide reliable data on the pattern of sexual dimorphism in the region. The data from these skulls is analysed using both univariate and multivariate statistics to derive discriminant functions that can be applied in sex estimation during personal identification. The results from the analyses are compared with those derived from other modern skeletal collections from northern and central Thailand. This shows that variation across the country is minimal. An on-line method of easily applying the results of the analysis to data from unknown skeletons is presented and freely available for use by practitioners of forensic anthropology.

Peak shifts and extinction under sex-specific selection

A well-known property of sexual selection combined with a cross-sex genetic correlation (rmf) is that it can facilitate a peak shift on the adaptive landscape. How do these diversifying effects of sexual selection + rmf balance with the constraints imposed by such sexual antagonism, to affect the macroevolution of sexual dimorphism? Here, I extend existing quantitative genetic models of evolution on complex adaptive landscapes. Beyond recovering classical predictions for the conditions promoting a peak shift, I show that when rmf is moderate to strong, relatively weak sexual selection is required to induce a peak shift in males only. Increasing the strength of sexual selection leads to a sexually concordant peak shift, suggesting that macroevolutionary rates of sexual dimorphism may be largely decoupled from the strength of within-population sexual selection. Accounting explicitly for demography further reveals that sex-specific peak shifts may be more likely to be successful than concordant shifts in the face of extinction, especially when natural selection is strong. An overarching conclusion is that macroevolutionary patterns of sexual dimorphism are unlikely to be readily explained by within-population estimates of selection or constraint alone.

Variation in body size of ringed seals (Pusa hispida hispida) across the circumpolar Arctic: evidence of morphs, ecotypes or simply extreme plasticity?

The ringed seal is a small phocid seal that has a northern circumpolar distribution. It has long been recognized that body size is variable in ringed seals, and it has been suggested that ecotypes that differ in size exist. This study explores patterns of body size (length and girth) and age-at-maturity across most of the Arctic subspecies’ range using morphometric data from 35 sites. Asymptotic lengths varied from 113 to 151 cm, with sites falling into five distinct size clusters (for each sex). Age-at-maturity ranged from 3.1 to 7.4 years, with sites that had early ages of sexual maturity generally having small length-at-maturity and small final body length. The sexes differed in length at some sites, but not in a consistent pattern of dimorphism. The largest ringed seals occurred in western Greenland and eastern Canada, and the smallest occurred in Alaska and the White Sea. Latitudinal trends occurred only within sites in the eastern Canadian Arctic. Girth (with length and season accounted for) was also highly variable but showed no notable spatial pattern; males tended to be more rotund than females. Genetic studies are needed, starting with the “giants” at Kangia (Greenland) and in northern Canada to determine whether they are genetically distinct ecotypes. Additional research is also needed to understand the ecological linkages that drive the significant regional size differences in ringed seals that were confirmed in this study, and also to understand their implications with respect to potential adaptation to climate change.

Sexual size dimorphism in the tail length of the Caspian Whip Snakes, Dolichophis caspius (Serpentes, Colubridae), in south-western Hungary

Sexual size dimorphism is widespread among snakes and has also been observed in lengths of body appendages such as in tails. Males typically possess longer tails than females and this dimorphism in tail length has generally been attributed to the importance of the tail in mating and reproduction. We used body size measurements, snout-vent length (SVL) and tail length (TL) as well as a body condition index (BCI) as a measure of quality in Caspian Whip Snakes from Hungary, in order to shed light on sexual dimorphism patterns. The SVL of males (1061 ± 133 mm, n = 25) were significantly longer than that of females (887 ± 208 mm, n = 41). However, the proportion of TL to total length was lower in males than in females (0.257 ± 0.018 and 0.274 ± 0.017, respectively). The BCI of females (386 ± 10) was significantly higher than that of males (343 ± 15). Females having proportionally longer tails compared to males seems to be the reverse of the usual trend. Selective pressures on the tails of female snakes are less obvious, as tail length may be linked to more than one function, and hence be simultaneously subjected to more than one type of selective force.

Sex-specific parenting and depression evoked by preoptic inhibitory neurons

SummaryThe role of preoptic GABAergic inhibitory neurons was addressed in parenting, anxiety and depression. Pup exposure and forced swimming resulted in similar c-Fos activation pattern in neurons expressing vesicular GABA transporter in the preoptic area with generally stronger labeling and different distributional pattern in females than in males. Chemogenetic stimulation of preoptic GABAergic cells resulted in elevated maternal motivation and caring behavior in females and mothers but aggression toward pups in males. Behavioral effects were the opposite following inhibition of preoptic GABAergic neurons suggesting their physiological relevance. In addition, increased anxiety-like and depression-like behaviors were found following chemogenetic stimulation of the same neurons in females, whereas previous pup exposure increased only anxiety-like behavior suggesting that not the pups, but overstimulation of the cells can lead to depression-like behavior. A sexually dimorphic projection pattern of preoptic GABAergic neurons was also identified, which could mediate sex-dependent parenting and associated emotional behaviors.

Sexual dimorphism in the size and shape of the non-obstetric pelvis across anthropoids.

The presence of sexual dimorphism in the birth canals of anthropoid primates is well documented, and birth canal dimorphism tends to be especially robust among species that give birth to relatively large neonates. However, it is less clear whether birth canal dimorphism is accompanied by dimorphism in parts of the pelvis not directly under selection for birth, particularly including bi-iliac breadth, biactetabular breadth, lengths of the ischium and ilium, and 3D shape. This study investigates the patterns of dimorphism among anthropoid primates in those parts of the pelvis which do not directly contribute to the bony birth canal, here termed the non-obstetric pelvis. 3D landmark data were collected on the bony pelves of 899 anthropoid primates. Specifically, landmark data were collected on parts of the pelvis not thought to be directly involved in selection for parturition, including portions of the posterior and superior ilium, acetabulum, and lateral ischium. Principal components analysis and Euclidean distance matrix analysis were used to ascertain sexual dimorphism in pelvic sizes and shapes within each species. Results show that dimorphism in non-obstetric pelvic size and shape exists across anthropoids, just as is seen in the birth canal. However, the magnitude of dimorphism in non-obstetric pelvic shape tends to be greater among anthropoid species that give birth to relatively large neonates compared with those birthing smaller neonates relative to maternal pelvic size. Though all anthropoids included in the study show some degree of sexual dimorphism in non-obstetric pelvic size and/or shape, species which give birth to large neonates relative to maternal pelvic size have the highest levels of dimorphism in pelvic shape. Moreover, the magnitude of dimorphism in certain parts of the non-obstetric pelvis mirrors patterns seen in the birth canal. The results of this study are promising for ascertaining pelvic dimorphism and relative neonate size in fossil primates, particularly in fragmentary remains which do not preserve a complete bony birth canal.

Exploratory Analysis of Color Forms' Variability in the Invasive Asian Lady Beetle Harmonia axyridis (Pallas 1773).

Simple SummaryIn the following study, methods of geometric morphometrics were used to identify invasive forms of Harmonia axyridis. The study confirms the efficiency of geometric morphometrics as a tool for identifying minimal shape plasticity in wing shape and patterns of sexual shape dimorphism among invasive forms. Although more detailed studies are needed for further clarity, the study demonstrates that these methods can analyze phenotypic differences among the forms and reveal subtle phenotypic changes that explain genetic alterations within an invasive H. axyridis species.The Asian ladybird (Harmonia axyridis Pallas), native to Asia, is one of the 100 most invasive species in the world and has spread worldwide. This study aimed to characterize color forms of H. axyridis in Croatia and to analyze the variability of wing shape between populations and indicated forms. Geometric morphometric methods were used to analyze a total of 129 left and right wings in males and 126 left and right wings in females of H. axyridis collected from four different sites in Croatia. The results show a significant difference in wing shapes between the studied forms. Each form had its own specific morphotype that likely originated under the influence of genetic changes in the species. This study demonstrates that the use of geometric morphometric analysis is effective in studying the variability in H. axyridis populations. As this study is the first of its kind, for further clarity, it is necessary to conduct additional studies on a larger number of sites and an equal number of individuals of all forms.

Evaluation of candidate genotype of immune gene MBL1 associated with udder health and performance traits in dairy cattle and buffalo of India

An investigation was conducted to identify polymorphism in mannose-binding lectin 1 (MBL1) gene and its effect on udder health and performance traits in dairy cattle and buffalo of India. Candidate single-nucleotide polymorphism (SNP) c.2534G > A of MBL1 gene was genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). All the possible genotypes for SNP c.2534G > A (GG, AG, and AA) were observed in the studied population. However, Sahiwal cows revealed dimorphic pattern (AG and GG). The effect of targetedSNP on incidence of mastitis wasevaluated and found to be significant. Animals with GG genotype were less susceptible to clinical mastitis and had comparatively lower somatic cell score (SCS) in Hardhenu cattle (P < 0.01) and Murrah buffalo (P < 0.05). Animals having GG genotype also exhibited significantly (P < 0.05) lower age at first calving (AFC). AG genotyped Murrah buffalo animals revealed significantly higher second lactation milk yield (P < 0.01). GG genotype with SCS and AFC could therefore be exploited as a promising candidate marker for the genetic improvement of udder health and AFC in dairy animals.

Intra- and Interspecific Variation in Sexual Dimorphism Patterns of Mud Crab Genus Scylla Along the Equatorial Region

Sexual dimorphism is generally obvious in brachyurans, and sexual dimorphism between species is of a higher degree to allow separation of trophic niches compared to the lower intraspecific variations between sexes. Mud crab genus Scylla are distributed along the Indo-West Pacific region, and species within this genus often exhibit overlapping niches and similar external morphologies. This study compared the intra- and interspecific sexual dimorphism patterns of three sympatric Scylla species from four distinct geographical locations along the equatorial region based on 24 morphometric characters. The consistency of sexual dimorphism patterns between locations was higher than between species. However, reproduction-related characters such as cheliped dimensions and abdomen width (AW) exhibited similar sexual dimorphism patterns across species. Discriminant function analysis based on the 23 morphometric ratios revealed the morphometric intraspecific divergence in all three Scylla species from the Asajaya mangrove forest. The cause for this regional intraspecific differentiation of mud crabs from the Asajaya mangrove forest remains unknown.