Fusako Mitsunaga

Sexual selection in Japanese macaques II: female mate choice and male-male competition

Mating and reproductive outcomes are the product of the potentially conficting strategies of breeding males and females. In a captive group of Japanese macaques, Macaca fuscata fuscatabehavioural, endocrine and genetic data were combined to assess the independent effects of male-male competition and female mate choice on mating and reproductive success. Males were ranked by social dominance and by their attractivity to females. Computer simulation and logistic regression analyses showed that male attractivity had a stronger effect than male dominance on both mating and reproductive outcome. Although male dominance and attractivity both significantly predicted mating success during fertile periods, only male attractivity significantly predicted actual male reproductive success. These results provide evidence that female mate choice can be a stronger determinant of mating and reproductive outcome in this species when male and female strategies are in conflict. The lack of a consistent correlation between male dominance rank and reproductive success in this species may be accounted for in part by female mate choice of socially subordinate males. Sires who were observed to mate with the mother during her fertile period were more likely to be socially dominant than sires who were not observed to do so. This observation suggests the existence of alternative mating strategies by subordinate males, which may also contribute to the lack of a consistent correlation between male dominance rank and reproductive success in this species.1997The Association for the Study of Animal Behaviour

Sexual selection in Japanese macaques I : female mate choice or male sexual coercion?

Mate choice is defined as a behavioural pattern in one sex which increases the probability of fertile matings with certain members of the opposite sex. The chosen sex may use force, however, to coerce matings from reluctant members of the choosing sex. In a confined group of Japanese macaques, Macaca fuscata fuscatahoused at the Primate Research Institute of Kyoto University, Japan, behavioural and endocrine data were combined to assess the validity of several mate-choice behaviours and the potential influence of sexual coercion. Preliminary evidence was found for both female mate choice of males and male sexual coercion of females. Both female proximity maintenance towards males and male aggression towards females were correlated with an increase in fertile matings. Most male aggression appeared to be the by-product of increased time spent in proximity due to female proximity maintenance, but some male aggression appeared to be sexual coercion. These results are interpreted in light of recent research on male sexual coercion, and a tentative model of mate choice for this species is proposed.1997The Association for the Study of Animal Behaviour

Male dominance rank and reproductive success in an enclosed group of Japanese macaques: with special reference to post-conception mating

The mating behaviour and reproductive success of male Japanese macaques (Macaca fuscata) were studied in relation to the female sexual cycles, which were monitored from the plasma profiles of gonadotropins and ovarian hormones. Based on observations of the mating behaviour during four successive mating seasons and paternity identification by DNA fingerprinting in 35 out of 37 offspring born in the subsequent birth seasons, the correlations between (1) male dominance rank and timing of mating, and (2) male dominance rank and reproductive success were examined. The results may be summarized as follows. (1) The number of copulations with ejaculation by any male was positively correlated with the male dominance rank, but not with the identified numbers of offspring fathered by each male. (2) Males could not choose ovulatory females as mating partners: the number of copulations with ejaculation with females during ovulatory weeks was not related to the males rank. Monopolized copulations in consortship were mostly observed between high-ranking males and non-lactating parous females after conception. (3) Paternity testing showed that the male copulating most frequently with a female was not the identified father in 11 out of 15 cases. Prediction of the fathers of offspring was difficult even from the number of copulations occurring at around the estimated time of ovulation. An adaptive explanation of these correlations is discussed.

SINE‐R.C2 (a Homo sapiens specific retroposon) is homologous to CDNA from postmortem brain in schizophrenia and to two loci in the Xq21.3/Yp block linked to handedness and psychosis

We investigated the retroviral/retroposon hypothesis of schizophrenia by generating sequences with PCR primers based on a retroviral sequence recovered by Yee et al. [1998: Schizophr Res 29:92] from a cDNA library from postmortem brain tissue from an individual with psychosis in a genomic region (Xq21.3) that has been tentatively linked to schizophrenia and schizoaffective disorder by Laval et al. [1998: Am. J. Med. Genet. (Neuropsychiatr. Genet.) 81:420-427]. Within the block of homology with Yp that was generated by a transposition between the chimpanzee and Homo sapiens we find two sequences, HS307 and HS408, with a high degree of homology to but not identity with the schizophrenic brain cDNA. The closest match of these three sequences is to a family of retroposons, that has evolved from the HERV-K family of endogenous retroviruses, some members of which (e.g., SINE-R.C2) appear to be specific to the human genome. This element has been reported as a cause of Fukuyama-type muscular dystrophy [Kobayashi et al., 1998: Nature 394:388-392]. Such retroposons, as agents of change in the human genome, provide a strategy for investigating pathogenesis. On account of their genomic location in a region that has been subject to change in the course of hominid evolution, and that may have a relationship to psychosis and/or cerebral asymmetry, we conclude that these particular insertions deserve further investigation.

Human-Specific SNP in Obesity Genes, Adrenergic Receptor Beta2 (ADRB2), Beta3 (ADRB3), and PPAR γ2 (PPARG), during Primate Evolution

Adrenergic-receptor beta2 (ADRB2) and beta3 (ADRB3) are obesity genes that play a key role in the regulation of energy balance by increasing lipolysis and thermogenesis. The Glu27 allele in ADRB2 and the Arg64 allele in ADRB3 are associated with abdominal obesity and early onset of non-insulin-dependent diabetes mellitus (NIDDM) in many ethnic groups. Peroxisome proliferator-activated receptor γ (PPARG) is required for adipocyte differentiation. Pro12Ala mutation decreases PPARG activity and resistance to NIDDM. In humans, energy-expense alleles, Gln27 in ADRB2 and Trp64 in ADRB3, are at higher frequencies than Glu27 and Arg64, respectively, but Ala12 in PPARG is at lower frequency than Pro12. Adaptation of humans for lipolysis, thermogenesis, and reduction of fat accumulation could be considered by examining which alleles in these genes are dominant in non-human primates (NHP). All NHP (P. troglodytes, G. gorilla, P. pygmaeus, H. agilis and macaques) had energy-thrifty alleles, Gly16 and Glu27 in ADRB2, and Arg64 in ADRB3, but did not have energy-expense alleles, Arg16, Gln27 and Trp64 alleles. In PPARG gene, all NHP had large adipocyte accumulating type, the Pro12 allele. Conclusions These results indicate that a tendency to produce much more heat through the energy-expense alleles developed only in humans, who left tropical rainforests for savanna and developed new features in their heat-regulation systems, such as reduction of body hair and increased evaporation of water, and might have helped the protection of entrails from cold at night, especially in glacial periods.

Gene expression profile of Th1 and Th2 cytokines and their receptors in human and nonhuman primates

Background  To date comparative knowledge concerning gene expression profiles of T‐helper 1(Th1)/Th2 cytokines and their receptors between human and non‐human primates is scarce.

One-step PCR to distinguish B virus from related primate alphaherpesviruses.

ABSTRACT By adding betaine to the PCR mixture, we previously established a PCR method to amplify a DNA segment of the glycoprotein G gene of B virus (BV) derived from a rhesus macaque. We have found that DNA of other BV strains derived from cynomolgus, pigtail, and lion-tailed macaques can also serve as the template in our PCR assay. Under the same conditions no product was obtained with DNA of simian agent 8 of green monkeys and Herpesvirus papio 2 of baboons, or the human herpes simplex viruses types 1 and 2. Thus, this PCR method is useful to discriminate BV from other closely related primate alphaherpesviruses.

Efficacy of a B virus gD DNA vaccine for induction of humoral and cellular immune responses in Japanese macaques

It is desirable to prevent dissemination of B virus (BV) in macaque colonies because transmission of BV to humans causes deadly encephalomyelitis. Vaccination of monkeys is one method that could confine spread of BV within macaque colonies. Availability of a BV DNA vaccine for use in macaques would eliminate the risk of working with infectious BV. Toward this end, we constructed a plasmid expressing the BV glycoprotein D (gD). Immunogenicity of this construct as a DNA vaccine was assessed in adult Japanese macaques by four intracutaneous injections at a dose of 500 microg per head. Results of enzyme-linked immunosorbent assay (ELISA) using a recombinant herpes simplex virus type 1 (HSV1) gD, a homologue of BV gD, showed that significant levels of antibody was induced in all vaccinated animals following each booster injection. Western blot of sera from vaccinated macaques confirmed the specific recognition of authentic BV gD. Immune sera were also demonstrated to contain neutralizing activity against infectious BV. Weak lymphoproliferative responses were also observed in vaccinated macaques using recombinant HSV1 gD as a stimulating antigen and flow cytometry analysis of one individual revealed the presence of HSV1 gD-responsive effector T cells. Thus, the BV gD DNA vaccine was demonstrated to induce both humoral and cellular immune responses in macaques which recognized BV gD.

Vasoformative disorder, resembling littoral cell angioma, of the spleen in a geriatric Japanese macaque (Macaca fuscata).

A 30-year-old female Japanese macaque showed marked splenomegaly. The enlarged spleen consisted of neoplastic proliferation of anastomosing vascular channels resembling morphologic structures of red pulp sinuses; occasionally, papillary fronds were seen in dilated channels. Immunohistochemically, the lining cells reacted to both endothelial cell (von Willebrand factor) and macrophage (macrophage scavenger receptor class A) markers, indicating features of littoral cells of the spleen. Based on the pathologic characteristics, particularly the presence of neoplastic cells with macrophage/histiocyte-like attributes, this tumor was regarded as littoral cell angioma; this is a rare benign splenic vascular tumor.

Blockade of menstrual cycle by thyroidectomy in Japanese monkeys (Macaca fuscata fuscata)

To examine the role of thyroid hormones in the seasonal breeding cycle in Japanese monkeys (Macaca fuscata fuscata), sexually mature females were thyroidectomized (n=6) in early December, during the midbreeding season, or they received sham operations (n=4). They were housed indoors individually, and blood samples were collected two to three times a week to monitor gonadotropin and gonadal steroid hormone secretions. Control monkeys exhibited ovulatory cycles during the breeding season. The mean dates of onset and end of the ovulatory cycles were October 22±13 d and February 25±14 d, respectively. These dates coincided well with those of our colonies under captivity. By contrast, three of the six thyroidectomized monkeys terminated ovulatory cycles immediately after operations; the remaining three monkeys ovulated only once or twice after thyroid removal. The mean dates of onset and end of the ovulatory cycles of thyroidectomized monkeys were October 18±4 d and December 31±4 d, respectively. This was a significantly earlier termination of the ovulatory cycles than in controls. Mean concentrations of plasma thyroxine of control monkeys were maintained throughout the experimental period, whereas plasma thyroxine concentrations of thyroidectomized monkeys decreased abruptly to undetectable levels. Thyroidectomized monkeys exhibited significantly higher levels of plasma prolactin (PRL) than controls. Moreover, even in control monkeys, plasma PRL increased during the transition out of the breeding season. These results suggest that thyroid hormones play an important role in the regulation of ovulatory cycles in Japanese monkeys, directory or indirectly, possibly by mediating the changes of PRL secretion.