Interactions between parents and infants,and infants-father separation in the common marmoset (Callithrix jacchus)

The New World monkey,Callithrix jacchus, diversely from most Old World primates, shares infant care among all family members. This paper intends to describe a pattern of infant care in the common marmoset, and to verify if the infant-father separation induces a depression reaction, such as found in other separation studies. In Experiment 1, 11 families (mother, father, and twin newborn infants) ofCallithrix jacchus were observed from 1st to 36th days of infants' life. It was noted that infants were carried most of the time in the beginning of life, and that from the 4th day on this care came mostly from the father. In Experiment 2, nine families were divided in three separation groups (15, 30, and 45 days of infants' life). Each group had a control and two experimental families. Removal of the father was done for three days, beginning at the indicated infants' ages. Results showed that upon removal of the father, the mother assumes the infants' care, and no depression reaction appeared.     

Alloparental Responsiveness to Newborns by Nonreproductive,Adult Male,Common Marmosets (Callithrix jacchus)

Parental care in mammals is influenced by sensory stimuli from infants, and by changes in the hormone levels of caretakers. To determine the responsiveness to infant cues in nonreproductive adult male common marmosets (Callithrix jacchus) with and without previous experience in caretaking, we exposed 12 males to newborn marmosets and assessed their cortisol plasma levels and behavioral response. Newborn marmosets housed in transparent enclosures were placed inside the cages of the adult male subjects. Males were exposed four times to two different experimental conditions: (a) newborn enclosures remained closed during the observation period and (b) newborn enclosures were opened during the observation period to allow direct social interaction by the adult males. Blood samples from adult males were collected after each behavioral observation trial to measure the levels of cortisol. The behavioral responses of adult males exposed to the closed and open newborn enclosures showed a significant difference only with respect to the frequency of displacements, where males moved among the quadrants of their own cages with greater frequency when the newborn enclosure was sealed. Experienced males approached newborn enclosures more frequently, spent more time in close proximity, and carried and recovered newborns more quickly than inexperienced males. The successive exposure to newborns increased the responsiveness in inexperienced males. The highest levels of plasma cortisol in adult males were recorded following periods of exposure to the sealed newborn enclosures. This suggests that successive exposure to newborns and previous alloparental caregiving experience while living in family groups influences the responsiveness of male marmosets to the sensory cues of newborns. Am. J. Primatol. 75:145‐152, 2013. © 2012 Wiley Periodicals, Inc.     

Behavioral and physiological suppression of fertility in subordinate marmoset monkeys

In laboratory groups of common marmosets (Callithrix jacchus jacchus), socially induced reproductive suppression among subordinates and offspring effectively maintained a monogamous breeding system. Male subordinates or male offspring were inhibited or restrained from showing sexual behavior, while similarly placed females could also suffer from complete ovarian failure. In well-established families, a familiarity or inbreeding taboo restricted reproduction among otherwise fertile offspring. However, only one daughter ovulated in any family, and in up to 50% of family groups, all daughters were inhibited from ovulating. This differential effect on daughters may have reflected a qualitative shift in the mother-daughter relationship: the ovulating daughter may have represented the next breeding female and may no longer have regarded the mother as an inhibitory influence. In newly established peer groups of pubertal and postpubertal offspring, one male and female dominated all others in each group and overtly inhibited sexual behavior in subordinates of their own sex. Ovulation was suppressed in all subordinate females because of inadequate gonadotrophin secretion. This was not related to increased secretion of cortisol or prolactin, but may have been related to hypothalamic inhibition of luteinizing hormone-releasing hormone (LHRH) secretion.     

Effects of sibling-rearing experience on future reproductive success in two species of callitrichidae

The survival rate for offspring of mothers who either had or did not have previous experience rearing younger siblings was compared in two callitrichid species, Callithrix jacchus and Saguinus oedipus. Offspring of mothers with sibling-rearing experience had a higher survival percentage than offspring of inexperienced mothers in both species. While 50–60% of offspring of inexperienced C. jacchus mothers survived, no offspring of inexperienced S. oedipus mothers survived. The results suggest that sibling-rearing experience is necessary for adequate maternal behavior in S. oedipus, but not necessary to the development of maternal behavior in C. jacchus. Effects of previous sibling-rearing experience of S. oedipus fathers on offspring survival were also examined. Whether the father had rearing experience was not related to the survival of their offspring.     

Genetic polymorphism and linkage of the sixth and seventh complement components (C6 and C7) in the common marmoset

Using polyacrylamide gel isoelectric focusing and standard specific hemolytic detection methods, genetic polymorphisms have been found in the sixth and seventh complement components (C6 and C7) in two laboratory groups of Common marmosets. The C6 locus is highly variable and the products of six alleles were observed; three C7 alleles were found. Comprehensive breeding data indicated that both sets of alleles are inherited in an autosomal codominant manner. Many of the C6 variants differed only by a minute charge interval. The C7 variant bands differed by large charge intervals and could only be clearly seen in plasmas that had been preincubated with neuraminidase. A linkage analysis of C6 and C7 phenotypes in three, two-generation families gives reasonable evidence that the two loci are linked in marmosets as they are in humans.This work was supported by a grant from the Advisory Board to the Research Councils.     

Intercellular communication between cultured granulosa cells of the marmoset (Callithrix jacchus)

Summary The influence of follicle-stimulating hormone, forskolin, insulin-like growth factor type I, epidermal growth factor, and 12-tetradecanoyl-phorbol-13-acetate on marmoset granulosa cell communication via gap junctions was investigated by morphological means and microinjection of carboxyfluorescein. Gap junctions between neighbouring granulosa cells were present in all groups. The number, but not length, of gap junctions between marmoset granulosa cells increased when the cells had been treated with follicle-stimulating hormone, insulin-like growth factor type I, and follicle-stimulating hormone plus insulin-like growth factor type I. No effect on gap junctions was seen, after exposure of the cells to the other three substances. Carboxyfluorescein and counting of the surrounding labelled cells showed that supplementation with follicle-stimulating hormone, forskolin, insulin-like growth factor type I and epidermal growth factor from the beginning of cultivation led to an increase in stained cells after 48 h. When treatment was started in 48 h cultures the substances reached their maximal activity within 30 min (forskolin and epidermal growth factor) or 3 h (follicle-stimulating hormone and insulin-like growth factor type I). Spreading of the fluorescen dye was inhibited when the medium was supplemented with 12-tetradecanoyl-phorbol-13-acetate. This effect was maximal after 30 min. Additive effects regarding the coupling of the cells were seen by combining of epidermal growth factor with follicle-stimulating hormone, but not with insulin-like growth factor type I or forskolin plus follicle-stimulating hormone.     

Monomorphic Region of the Serotonin Transporter Promoter Gene in New World Monkeys

Genetic variation in the human serotonin system has long been studied because of its functional consequences and links to various neuropsychiatric and behavior‐related disorders. Among non‐human primates, the common marmosets (Callithrix jacchus) and tufted capuchins monkeys (Cebus apella) are becoming increasingly used as models to study the effects of genes, environments, and their interaction on physiology and complex behavior. In order to investigate the independent functions of and potential interactions between serotonin‐related genes, anxiety and neuropsychiatric disorders, we analyzed the presence and variability of the serotonin transporter gene‐linked polymorphic region (5‐HTTLPR) in marmoset and capuchin monkeys. By PCR and using heterologous primers from the human sequence, we amplified and then sequenced the corresponding 5‐HTT region in marmosets and capuchins. The resulting data revealed the presence of a tandem repeat sequence similar to that described in humans, but unlike humans and other Old World primates, no variable length alleles were detected in these New World monkeys, suggesting that if serotonin transporter is involved in modulating behavior in these animals it does so through different molecular mechanisms. Am. J. Primatol. 74:1028‐1034, 2012. © 2012 Wiley Periodicals, Inc.     

Karyotype of Callithrix mauesi (Callitrichidae,Primates) and its relations with those of C. emiliae and C. jacchus

A study was conducted on the most recently described marmoset species, Callithrix mauesi, and the results obtained were compared to those previously reported for the karyotypes of C. jacchus and C. emiliae. No mechanism of chromosome rearrangement differentiates the karyotypes of C. mauesi (2n = 44) and C. emiliae (2n = 44), which diverge from C. jacchus (2n = 46) by a Robertsonian translocation and a paracentric inversion. C. mauesi, like C. emiliae, presents telomeric constitutive heterochromatin in various chromosomes, forming large heterochromatic blocks in some. This does not occur in C. jacchus, which basically presents centromeric constitutive heterochromatin. The karyotype of C. mauesi differs from that of C. emiliae only by the amount and distribution of this telomeric constitutive heterochromatin. One of the chromosomes presenting a heterochromatic block in C. mauesi is chromosome X, a fact not previously reported in the Order Primates. The present chromosome data show that C. mauesi is closer to C. emiliae than to C. jacchus, in agreement with its inclusion in the C. argentata group. In the present paper, we describe for the first time, at the chromosome level, chimerism between fraternal twins of the same sex (XY/XY), with the heterochromatic block of pair 2 being the marker. © 1994 Wiley-Liss, Inc.