Genetic characterization of rhesus macaques (Macaca mulatta) in Nepal

Indian-origin rhesus macaques (Macaca mulatta) have long served as an animal model for the study of human disease and behavior. Given the current shortage of Indian-origin rhesus, many researchers have turned to rhesus macaques from China as a substitute. However, a number of studies have identified marked genetic differences between the Chinese and Indian animals. We investigated the genetic characteristics of a third rhesus population, the rhesus macaques of Nepal. Twenty-one rhesus macaques at the Swoyambhu Temple in Kathmandu, Nepal, were compared with more than 300 Indian- and Chinese-origin rhesus macaques. The sequence analyses of two mitochondrial DNA (mtDNA) loci, from the HVS I and 12 S rRNA regions, showed that the Nepali animals were more similar to Indian-origin than to Chinese-origin animals. The distribution of alleles at 24 short tandem repeat (STR) loci distributed across 17 chromosomes also showed greater similarity between the Nepali and Indian-origin animals. Finally, an analysis of seven major histocompatibility complex (MHC) alleles showed that the Nepali animals expressed Class I alleles that are common to Indian-origin animals, including Mamu-A*01. All of these analyses also revealed a low level of genetic diversity within this Nepali rhesus sample. We conclude that the rhesus macaques of Nepal more closely resemble rhesus macaques of Indian origin than those of Chinese origin. As such, the Nepali rhesus may offer an additional resource option for researchers who wish to maintain research protocols with animals that possess key genetic features characteristic of Indian-origin rhesus macaques.     

Pathogenicity of simian-human immunodeficiency virus SHIV-89.6P and SIVmac is attenuated in cynomolgus macaques and associated with early T-lymphocyte responses

Because most studies of AIDS pathogenesis in nonhuman primates have been performed in Indian-origin rhesus macaques (Macaca mulatta), little is known about lentiviral pathogenicity and control of virus replication following infection of alternative macaque species. Here, we report the consequences of simian-human immunodeficiency virus SHIV-89.6P and SIVmac251 infection in cynomolgus (Macaca fascicularis) and rhesus macaques of Chinese origin. Compared to the pathogenicity of the same viruses in Indian rhesus macaques, both cynomolgus and Chinese rhesus macaques showed lower levels of plasma virus. By 9 to 10 months after infection, both viruses became undetectable in plasma more frequently in cynomolgus than in either Chinese or Indian rhesus macaques. Furthermore, after SHIV-89.6P infection, CD4+ T-cell numbers declined less and survival was longer in cynomolgus and Chinese rhesus macaques than in Indian rhesus macaques. This attenuated pathogenicity was associated with gamma interferon ELISPOT responses to Gag and Env that were generated earlier and of higher frequency in cynomolgus than in Indian rhesus macaques. Cynomolgus macaques also developed higher titer neutralizing antibodies against SHIV-89.6 at 10 and 20 weeks postinoculation than Indian rhesus macaques. These studies demonstrate that the pathogenicity of nonhuman primate lentiviruses varies markedly based on the species or geographic origin of the macaques infected and suggest that the cellular immune responses may contribute to the control of pathogenicity in cynomolgus macaques. While cynomolgus and Chinese rhesus macaques provide alternative animal models of lentiviral infection, the lower levels of viremia in cynomolgus macaques limit the usefulness of infection of this species for vaccine trials that utilize viral load as an experimental endpoint.     

Variation in CCL3L1 copy number in rhesus macaques (Macaca mulatta)

We used real-time quantitative PCR (qPCR) methodology to examine copy number variation (CNV) of the CCL3L1 gene among pure Indian-origin, pure Chinese-origin, and hybrid Indian-Chinese rhesus macaques (Macaca mulatta). CNV among purebred macaques fell within expected ranges, with Indian macaques having lower copy numbers than those of Chinese macaques. Compared with the purebred macaques, Indian-Chinese hybrid rhesus macaques showed much greater variance in copy number and an intermediate average copy number. Copy numbers of CCL3L1 in rhesus macaque trios (sire, dam, and offspring) were consistent with Mendelian inheritance.     

Genetic studies of human apolipoproteins

Summary Apolipoprotein H (APO H) has recently been identified as a structural component of chylomicrons, very low-density lipoproteins (VLDL), low-density lipoproteins (LDL), and high-density lipoproteins (HDL). Although the precise metabolic function of APO H in lipid metabolism is not certain, it has been suggested that APO H may be involved in triglyceride (TG) metabolism. In addition to the previously described quantitative polymorphism, we have recently detected a common qualitative polymorphism at the APO H structural locus. To test the role of APO H genetic variation in determining lipoprotein and lipid levels, we have estimated the allelic effects of APO H variation on TG, VLDL, LDL, HDL, HDL3, and total cholesterol on 356 Nigerian blacks(189 males, 167 females). While no significant effect of phenotype was observed on lipoprotein levels, the effect of interaction between phenotype and gender was significant. Therefore, data on males and females were analyzed separately using analysis of variance after adjusting for age and body mass index. Logarithmic transformation of pertinent variables was done to bring the distribution of the variables closer to normality. A statistically significant effect of phenotype was observed on triglyceride levels in females only (P<0.05). Further analysis of this phenotypic effect revealed that it is due to the impact of the APO H ^* 3 allele, which raises triglycerides by 9.92 mg/dl as compared to the common allele, APO H ^* 2. These findings are in accordance with the postulated role of APO H in triglyceride metabolism. On the basis of its sex-specific effect, we propose a hypothesis that may explain the combined influence of the quantitative and qualitative polymorphisms at the APO H locus on triglyceride levels in females.     

Identifying human-rhesus macaque gene orthologs using heterospecific SNP probes

We genotyped a Chinese and an Indian-origin rhesus macaque using the Affymetrix Genome-Wide Human SNP Array 6.0 and cataloged 85,473 uniquely mapping heterospecific SNPs. These SNPs were assigned to rhesus chromosomes according to their probe sequence alignments as displayed in the human and rhesus reference sequences. The conserved gene order (synteny) revealed by heterospecific SNP maps is in concordance with that of the published human and rhesus macaque genomes.Using these SNPs' original human rs numbers, we identified 12,328 genes annotated in humans that are associated with these SNPs, 3674 of which were found in at least one of the two rhesus macaques studied. Due to their density, the heterospecific SNPs allow fine-grained comparisons, including approximate boundaries of intra- and extra-chromosomal rearrangements involving gene orthologs, which can be used to distinguish rhesus macaque chromosomes from human chromosomes.     

Quantitative Genetics of Response to Novelty and Other Stimuli by Infant Rhesus Macaques (Macaca mulatta) Across Three Behavioral Assessments

Primate behavior is influenced by both heritable factors and environmental experience during development. Previous studies of rhesus macaques (Macaca mulatta) examined the effects of genetic variation on expressed behavior and related neurobiological traits (heritability and/or genetic association) using a variety of study designs. Most of these prior studies examined genetic effects on the behavior of adults or adolescent rhesus macaques, not in young macaques early in development. To assess environmental and additive genetic variation in behavioral reactivity and response to novelty among infants, we investigated a range of behavioral traits in a large number (N?=?428) of pedigreed infants born and housed in large outdoor corrals at the Oregon National Primate Research Center (ONPRC). We recorded the behavior of each subject during a series of brief tests, involving exposure of each infant to a novel environment, to a social threat without the mother present, and to a novel environment with its mother present but sedated. We found significant heritability (h ² ) for willingness to move away from the mother and explore a novel environment (h ² ?=?0.25?±?0.13; P?=?0.003). The infants also exhibited a range of heritable behavioral reactions to separation stress or to threat when the mother was not present (h ² ?=?0.23?±?0.13–0.24?±?0.15, P?<?0.01). We observed no evidence of maternal environmental effects on these traits. Our results extend knowledge of genetic influences on temperament and reactivity in nonhuman primates by demonstrating that several measures of behavioral reactivity among infant rhesus macaques are heritable.     

Genetic characterization of Indian-origin and Chinese-origin rhesus macaques (Macaca mulatta)

Genetic differences between Indian-origin and Chinese-origin rhesus macaques are as great as those between some primate species and can influence the results of experiments in which both are used as animal models for the study of the same human diseases. Unfortunately, many breeding facilities do not know with certainty the origin of the founders of their rhesus breeding colonies. Here I summarize the most definitive of the genetic traits among the microsatellite (STR) loci and mitochondrial DNA sequences that my laboratory previously reported to characterize Indian-origin and Chinese-origin rhesus macaques and then estimate the frequencies of these traits and their reliability as indicators of country of origin. The expression of diagnostic traits at two or more of four different unlinked loci provides a nearly 100% reliability in distinguishing rhesus macaques of Indian and Chinese origin.     

Age- and gender-related changes in body size, adiposity, and endocrine and metabolic parameters in free-ranging rhesus macaques.

Normative age- and gender-related changes in body composition, serum lipids, testosterone, and insulin-like growth factor (IGF-1) were examined in the Cayo Santiago free-ranging rhesus macaques. In both adult males and females, body weights, crown-rump lengths, and circumference of the limbs were lowest in the oldest group (20+ years of age) as compared with other adult age classes. Body fat, as reflected in subcutaneous fatfold thickness and waist/thigh ratios, were higher in adult females than adult males. This gender dimorphism was first detectable among the 6-9 year old age group. Greatest body fat among females was observed in the 10-14 age group, whereas in males the highest values were observed in the 15-19 age group. Differences in body composition were also observed with respect to reproductive status. Although there were no gender differences in overall cholesterol levels, there were age-related differences between males and females, and only in males were cholesterol values positively related to adiposity. There were no age- or gender-related differences in triglyceride values, but levels were significantly higher in pregnant females in comparison with other reproductive states. Levels of testosterone were not significantly related to any morphometric parameter and values did not decrease significantly with age. Levels of IGF-1 exhibited a significant age-related decrease among adult males, and females had higher levels independent of age. The similarities between the present findings and human studies suggest that further studies in the free-ranging rhesus macaques would provide a bridge between studies of laboratory-housed primates and studies of human beings with respect to the etiology of obesity and life-history changes in body composition and endocrine and metabolic parameters.     

Evaluating Dominance Styles in Assamese and Rhesus Macaques

Researchers have suggested that several types of agonistic and affiliative behavior covary as a set of species-specific traits, and have used the term dominance style to describe the covariation. We compared measures of dominance style between a group of Assamese macaques (Macaca assamensis) and a group of rhesus macaques (M. mulatta), though kinship information was unknown. Assamese and rhesus female-female dyads each showed a low proportion of counter aggression and a low conciliatory tendency, suggesting that they have despotic social relationships. They also showed a despotic pattern on several other types of agonistic and affiliative behavior, such as approach outcomes and grooming distributions, which is consistent with the covariation of dominance style traits. Assamese male-male dyads showed relatively high levels of reconciliation and counter aggression versus other macaque males portrayed in the literature, suggesting that Assamese males have a tolerant dominance style. Insofar as macaque dominance style depends on the behavior of females, we suggest that Assamese macaques, like rhesus macaques, have despotic social relationships, which contrasts with evidence of a strong correlation between phylogeny and dominance style in macaques. Further, our results indicate that strong male bonding and tolerant dominance relationships among males are independent of female dominance style. Lastly, some measures of agonistic behavior, such as rate of aggression or proportion of bites, are likely altered in competitive environments and thus are not useful indicators of dominance style.     

Genetic influences on growth traits of BMI: a longitudinal study of adult twins

Objective: To investigate the interplay between genetic factors influencing baseline level and changes in BMI in adulthood. Methods and Procedures: A longitudinal twin study of the cohort of Finnish twins (N = 10,556 twin individuals) aged 20–46 years at baseline was conducted and followed up 15 years. Data on weight and height were obtained from mailed surveys in 1975, 1981, and 1990. Results: Latent growth models revealed a substantial genetic influence on BMI level at baseline in males and females (heritability (h²) 80% (95% confidence interval 0.79–0.80) for males and h² = 82% (0.81, 0.84) for females) and a moderate‐to‐high influence on rate of change in BMI (h² = 58% (0.50, 0.69) for males and h² = 64% (0.58, 0.69) for females). Only very weak evidence for genetic pleiotropy was observed; the genetic correlation between baseline and rate of change in BMI was very modest (−0.070 (–0.13, −0.068) for males and 0.04 (0.00, 0.08) for females. Discussion: Our population‐based results provide a basis for identifying genetic variants for change in BMI, in particular weight gain. Furthermore, they demonstrate for the first time that such genetic variants for change in BMI are likely to be different from those affecting level of BMI.     

Whole-genome sequencing and analysis of the Malaysian cynomolgus macaque (Macaca fascicularis) genome

ABSTRACT: BACKGROUND: The genetic background of the cynomolgus macaque (Macaca fascicularis) is made complex by the high genetic diversity, population structure, and gene introgression from the closely related rhesus macaque (Macaca mulatta). Herein we report the whole-genome sequence of a Malaysian cynomolgus macaque male with more than 40-fold coverage, which was determined using a resequencing method based on the Indian rhesus macaque genome. RESULTS: We identified approximately 9.7 million single nucleotide variants (SNVs) between the Malaysian cynomolgus and the Indian rhesus macaque genomes. Compared with humans, a smaller nonsynonymous/synonymous SNV ratio in the cynomolgus macaque suggests more effective removal of slightly deleterious mutations. Comparison of two cynomolgus (Malaysian and Vietnamese) and two rhesus (Indian and Chinese) macaque genomes, including previously published macaque genomes, suggests that Indochinese cynomolgus macaques have been more affected by gene introgression from rhesus macaques. We further identified 60 nonsynonymous SNVs that completely differentiated the cynomolgus and rhesus macaque genomes, and that could be important candidate variants for determining species-specific responses to drugs and pathogens. The demographic inference using the genome sequence data revealed that Malaysian cynomolgus macaques have experienced at least three population bottlenecks. CONCLUSIONS: This list of whole-genome SNVs will be useful for many future applications, such as an array-based genotyping system for macaque individuals. High-quality whole-genome sequencing of the cynomolgus macaque genome may aid studies on finding genetic differences that are responsible for phenotypic diversity in macaques and may help control genetic backgrounds among individuals.     

Prevalence of dyslipidemia and mean blood lipid values in Taiwan: results from the Nutrition and Health Survey in Taiwan (NAHSIT, 1993-1996)

This paper reports the blood lipid status of people aged 4 years and older in Taiwan. The data is based on the Nutrition and Health Survey in Taiwan (NAHSIT: 1993-1996), which adopted a multi-stage, stratified clustering sampling scheme. Altogether, 5097 subjects (2451 males and 2646 females) had data on triglyceride and 5643 subjects (2736 males and 2907 females) had data on cholesterol. We found that (a) cholesterol levels of males were lower than females in mid-to old age group (> or = 45 years old); (b) triglyceride values of females were lower than males in young adulthood (19-44 years), but higher than males after the age of 45 years, and (c) adult females had higher HDL-C value and lower ratio of total cholesterol to HDL-C than males. The prevalence of hypercholesterolemia was 10.2% in adult males and 12.6% in mid-to-old aged men, and that in females was 11.2% and 24.4%, respectively. The prevalence of hypertriglyceridemia was 13.4% and 6.1% in adult males and females (> or = 19 years as a whole), respectively. It was 12.3% in mid-to-old aged men (> or = 45 years), and 11.9% in women. The mean cholesterol values were similar to values of several previous surveys in different areas of Taiwan. But it was higher than those in some areas of Mainland China, and lower than those of western countries. People in metropolitan cities had a higher level of blood cholesterol than other areas. The average triglyceride values of males and females were higher than those of previous studies in Taiwan and of people in Mainland China. Mountainous stratum with predominantly aboriginal residents had higher level of triglycerides and body mass index (BMI) than other strata. The associations between dietary intakes of men and women and blood lipids were examined controlling for age and BMI. Result showed that Keys score, which was derived from saturated fat, polyunsaturated fat and dietary cholesterol of a 24-hour recall, was positively related to blood cholesterol and LDL-C in men, but not in women. Average alcohol intakes per day were related to HDL-C positively, but LDL-C negatively in men and women. The regional differences in blood lipid profiles in Taiwan are consistent with the dietary and life-style variations island-wide.     

Molecular Evidence for Distinct Genotypes of Monkey B Virus (Herpesvirus Simiae) Which Are Related to the Macaque Host Species

Although monkey B virus (herpesvirus simiae; BV) is common in all macaque species, fatal human infections appear to be associated with exposure to rhesus macaques (Macaca mulatta), suggesting that BV isolates from rhesus monkeys may be more lethal to nonmacaques than are BV strains indigenous to other macaque species. To determine if significant differences that would support this supposition exist among BV isolates, we compared multiple BV strains isolated from rhesus, cynomolgus, pigtail, and Japanese macaques. Antigenic analyses indicated that while the isolates were very closely related to one another, there are some antigenic determinants that are specific to BV isolates from different macaque species. Restriction enzyme digest patterns of viral DNA revealed marked similarities between rhesus and Japanese macaque isolates, while pigtail and cynomolgus macaque isolates had distinctive cleavage patterns. To further compare genetic diversity among BV isolates, DNA sequences from two regions of the viral genome containing genes that are conserved (UL27 and US6) and variable (US4 and US5) among primate alphaherpesviruses, as well as from two noncoding intergenic regions, were determined. From these sequence data and a phylogenetic analysis of them it was evident that while all isolates were closely related strains of BV, there were three distinct genotypes. The three BV genotypes were directly related to the macaque species of origin and were composed of (i) isolates from rhesus and Japanese macaques, (ii) cynomolgus monkey isolates, and (iii) isolates from pigtail macaques. This study demonstrates the existence of different BV genotypes which are related to the macaque host species and thus provides a molecular basis for the possible existence of BV isolates which vary in their levels of pathogenicity for nonmacaque species.     

A Large‐Scale SNP‐Based Genomic Admixture Analysis of the Captive Rhesus Macaque Colony at the California National Primate Research Center

Some breeding facilities in the United States have crossbred Chinese and Indian rhesus macaque (Macaca mulatta) founders either purposefully or inadvertently. Genetic variation that reflects geographic origins among research subjects has the potential to influence experimental outcomes. The use of animals from different geographic regions, their hybrids, and animals of varying degrees of kinship in an experiment can obscure treatment effects under study because high interanimal genetic variance can increase phenotypic variance among the research subjects. The intent of this study, based on a broad genomic analysis of 2,808 single nucleotide polymorphisms (SNPs), is to ensure that only animals estimated to be of pure Indian or Chinese ancestry, based on both demographic and genetic information, are used as sources of infants for derivation and expansion of the California National Primate Research Center's (CNPRC) super‐Specific Pathogen Free (SSPF) rhesus macaque colony. Studies of short tandem repeats (STRs) in Indian and Chinese rhesus macaques have reported that heterozygosity of STRs is higher in Chinese rhesus macaques than in Indian rhesus macaques. The present study shows that heterozygosity of SNPs is actually higher in Indian than in Chinese rhesus macaques and that the Chinese SSPF rhesus macaque colony is far less differentiated from their founders compared to the Indian‐origin animals. The results also reveal no evidence of recent gene flow from long‐tailed and pig‐tailed macaques into the source populations of the SSPF rhesus macaques. This study indicates that many of the long‐tailed macaques held in the CNPRC are closely related individuals. Most polymorphisms shared among the captive rhesus, long‐tailed, and pig‐tailed macaques likely predate the divergence among these groups. Am. J. Primatol. 74:747‐757, 2012. © 2012 Wiley Periodicals, Inc.     

Plasma cholesterol levels in free-ranging macaques compared with captive macaques and humans

Plasma total cholesterol in free-ranging Japanese macaques (Macaca fuscata) on Koshima islet and in free-ranging long-tailed macaques (Macaca fascicularis) at Pangandaran in Indonesia was found to occur at very low levels compared with captive macaques and humans. Although total cholesterol levels in captive macaques were lower than humans, differences in HDL cholesterol levels were only small. In both sexes of wild and captive Japanese macaques, total cholesterol levels decreased from birth through to young adulthood but then increased in adult females of the captive group. In contrast, the value for adult females of the wild troop remained at a low level. Low TCH levels in adult females of the wild Japanese macaque troop may be due to a low energy intake and may have caused a delay in the onset of sexual maturation. Plasma TCH levels increased with the addition of 0.1% dietary cholesterol over six weeks in captive long-tailed macaques. That the cholesterol value after six weeks was dependent on cholesterol levels prior to supplementation indicates that captive macaques are slightly saturated with cholesterol.     

Social Relationships in Free-Ranging Male Macaca arctoides

Macaque social relationships differ greatly between species. Based on captive studies that focus mainly on females, researchers have classified stumptail macaque (Macaca arctoides) social relationships as tolerant, as indicated by a high rate of affiliation, frequent aggression, and symmetrical conflicts. To accumulate more data on male social relationships, which are relatively understudied, and to generate comparative data, we investigated male social relationships in a provisioned group of 68 free-ranging, naturally dispersing stumptail macaques in southern Thailand. We collected continuous focal animal and ad libitum data on 7 adult and 2 subadult males, recording social behavior during 283 contact hours between December 2006 and March 2007. Stumptail macaques of this population were less tolerant than predicted based on previous studies on captive groups: Rates of spatial proximity, affiliation, and aggression were low, most males directed affiliative behavior toward higher-ranking males, and conflicts were generally of low intensity and relatively asymmetrical. Thus, male stumptail macaques of the focal group appear to differ in their social style from a previous study of a captive group that mainly comprised of females. In some traits, they are even more intolerant than rhesus macaques, an intensively studied intolerant macaque species. We also compare our data on stumptail macaque males to those on other male macaques, but available data are too sparse to draw final conclusions.     

The genetic basis for mating-induced sex differences in starvation resistance in Drosophila melanogaster

Multiple genetic and environmental factors interact to influence starvation resistance, which is an important determinant of fitness in many organisms, including Drosophila melanogaster. Recent studies have revealed that mating can alter starvation resistance in female D. melanogaster, but little is known about the behavioral and physiological mechanisms underlying such mating-mediated changes in starvation resistance. In the present study, we first investigated whether the effect of mating on starvation resistance is sex-specific in D. melanogaster. As indicated by a significant sex × mating status interaction, mating increased starvation resistance in females but not in males. In female D. melanogaster, post-mating increase in starvation resistance was mainly attributed to increases in food intake and in the level of lipid storage relative to lean body weight. We then performed quantitative genetic analysis to estimate the proportion of the total phenotypic variance attributable to genetic differences (i.e., heritability) for starvation resistance in mated male and female D. melanogaster. The narrow-sense heritability (h²) of starvation resistance was 0.235 and 0.155 for males and females, respectively. Mated females were more resistant to starvation than males in all genotypes, but the degree of such sexual dimorphism varied substantially among genotypes, as indicated by a significant sex × genotype interaction for starvation resistance. Cross-sex genetic correlation was greater than 0 but less than l for starvation resistance, implying that the genetic architecture of this trait was partially shared between the two sexes. For both sexes, starvation resistance was positively correlated with longevity and lipid storage at genetic level. The present study suggests that sex differences in starvation resistance depend on mating status and have a genetic basis in D. melanogaster.     

Analysis of immunoglobulin,complements and CRP levels in serum of captive northern pig-tailed macaques (Macaca leonina)

The northern pig-tailed macaque(NPM,Macaca leonina) has become a widely used animal model in biomedical research. In this study, we measured serum immunoglobulin IgG, IgM, IgA, complement C3, C4 and CRP levels in 3-11 year old captive northern pig-tailed macaques using HITACHI 7600-20 automated chemistry analyzer in order to determine the influences of age and gender on these items. The results showed that serum IgA, IgM, C3 and C4 levels were not correlated with age(P0.05), while serum IgG levels increased progressively with age(r=0.202;P=0.045). Serum IgG, IgA, IgM and C3 levels were higher in females than in males(P0.05). Moreover, serum C3 concentration was both positively and strongly correlated with that of C4(r=0.700; P0.0001). This study provides basic serum immunoglobulin and complement data of captive northern pig-tailed macaques, which may prove useful for future breeding efforts and biomedical research.     

Genetic characterization of wild and captive rhesus macaques in China

The genetic structures of wild and captive rhesus macaque populations within China were compared by analyzing the mtDNA sequences of 203 captive-bred Chinese rhesus macaques with 77 GenBank sequences from wild-caught animals trapped throughout China. The genotypes of 22 microsatellites of captive Chinese rhesus macaques were also compared with those of captive Indian animals. The Chinese population is significantly differentiated from the Indian population and is more heterogeneous. Thus, compared with Indian rhesus macaques the phenotypic variance of traits with high heritability will be inflated in Chinese animals. Our data suggest that the western Chinese provinces have more subdivided populations than the eastern and southern Chinese provinces. The southern Chinese populations are the least structured and might have been more recently established. Human-mediated interbreeding among captive Chinese populations has occurred, implying that Chinese breeding strategies can influence the interpretation of biomedical research in the USA.     

Sex-specific gene expression in the blood of four primates

Blood is an important non-reproductive tissue, but little is known about the sex-specific gene expressions in the blood. Therefore, we investigated sex-specific gene expression differences in the blood tissues of four primates, rhesus macaques (Macaca mulatta), Tibetan macaques (M. thibetana), yellow baboons (Papio cynocephalus), and humans. We identified seven sex-specific differentially expressed genes (SDEGs) in each non-human primate and 31 SDEGs in humans. The four primates had only one common SDEG, MAP7D2. In humans, immune-related SDEGs were identified as up-regulated, but also down-regulated in females. We also found that most of the X-Y gene pairs had similar expression levels between species, except pair EIF1AY/EIF1AX. The expression level of X-Y gene pairs of rhesus and Tibetan macaques showed no significant differential expression levels, while humans had six significant XY-biased and three XX-biased X-Y gene pairs. Our observed sex differences in blood should increase understanding of sex differences in primate blood tissue.