Chromosome painting in two genera of South American monkeys: species identification, conservation, and management

Experiences of Animal Loss and Grief among Zoo Professionals and Volunteers: A Qualitative Study

Zoo professionals and volunteers play essential roles in the wellbeing and conservation of a diverse array of animal species. Despite the growing body of literature revealing the psychological impacts of pet loss, there remains a dearth of information describing the experience of animal loss among those who work in zoo settings. This qualitative study explored the personal experiences of zoo animal loss among volunteers (n = 12), animal care and health professionals (ACHPs) (n = 135), and other zoo staff (n = 35) who participated in a larger mixed-method study. Participants responded to five open-ended questions exploring their most significant zoo animal death loss, where or from whom they found the most support, how the zoo community could better support them, advice for zoo leaders, and other thoughts about their grief and animal-related loss experiences. Using thematic analysis, two key themes were identified: the lasting toll of zoo animal loss and zoo professionals' and volunteers' interpersonal experiences. Participants described their experiences with animal transfers and both expected and unexpected deaths. Requests for support focused on better communication, grief resources, and opportunities to recognize and mourn animal losses. These findings suggest that zoo animal loss can negatively impact zoo professionals' and volunteers' psychological health.

Evolution of the Human Chromosome 13 Synteny: Evolutionary Rearrangements, Plasticity, Human Disease Genes and Cancer Breakpoints

The history of each human chromosome can be studied through comparative cytogenetic approaches in mammals which permit the identification of human chromosomal homologies and rearrangements between species. Comparative banding, chromosome painting, Bacterial Artificial Chromosome (BAC) mapping and genome data permit researchers to formulate hypotheses about ancestral chromosome forms. Human chromosome 13 has been previously shown to be conserved as a single syntenic element in the Ancestral Primate Karyotype; in this context, in order to study and verify the conservation of primate chromosomes homologous to human chromosome 13, we mapped a selected set of BAC probes in three platyrrhine species, characterised by a high level of rearrangements, using fluorescence in situ hybridisation (FISH). Our mapping data on Saguinus oedipus, Callithrix argentata and Alouatta belzebul provide insight into synteny of human chromosome 13 evolution in a comparative perspective among primate species, showing rearrangements across taxa. Furthermore, in a wider perspective, we have revised previous cytogenomic literature data on chromosome 13 evolution in eutherian mammals, showing a complex origin of the eutherian mammal ancestral karyotype which has still not been completely clarified. Moreover, we analysed biomedical aspects (the OMIM and Mitelman databases) regarding human chromosome 13, showing that this autosome is characterised by a certain level of plasticity that has been implicated in many human cancers and diseases.

Reorganization of the Y Chromosomes Enhances Divergence in Israeli Mole Rats Nannospalax ehrenbergi (Spalacidae, Rodentia): Comparative Analysis of Meiotic and Mitotic Chromosomes

The Y chromosome in mammals is variable, even in closely related species. Middle East blind mole rats Nannospalax ehrenbergi demonstrate autosomal variability, which probably leads to speciation. Here, we compare the mitotic and meiotic chromosomes of mole rats. For the first time, we studied the behavior of their sex chromosomes in the meiotic prophase I using electron microscopy and immunocytochemical analysis. Unexpectedly, the sex chromosomes of the 52- and 60-chromosome forms of mole rats showed different synaptic and recombination patterns due to distinct locations of the centromeres on the Y chromosomes. The absence of recombination in the 60-chromosome form, the asymmetric synapsis, and the short-term disturbance in the synaptic co-orientation of the telomeric regions of the X and Y chromosomes were revealed as specific features of mole rat sex bivalents. We suggest several scenarios of Y chromosome alteration in connection with species differentiation in mole rats.

Night Monkey Hybrids Exhibit De Novo Genomic and Karyotypic Alterations: The First Such Case in Primates

Using molecular chromosomal analyses, we discovered night monkey hybrids produced in captivity from matings between a female Aotus azarae boliviensis (2n = 50) and a male Aotus lemurinus griseimembra (2n = 53). The parents produced seven offspring in total, including one male and six females-a pattern consistent with Haldane's rule. Chromosomal studies were conducted on four of the hybrid offspring. Two of them showed relatively "simple" mixture karyotypes, including different chromosome numbers (2n = 51, 52), which were formed because of a heteromorphic autosome pair in the father (n = 26, 27). The other two hybrid monkeys exhibited de novo genomic and karyotypic alterations. Detailed analysis of the alterations revealed that one individual carried a mixture karyotype of the two parental species and an X chromosome trisomy (53,XXX). The second individual displayed trisomy of chromosome 18 (52,XX,+18) and a reciprocal translocation between autosomes 21 and 23 (52,XX,+18,t(21;23)). Interestingly, the second monkey exhibited mosaicism among blood cells (mos52,XX,+18[87]/52,XX,+18,t(21;23)[85]), but only a single karyotype (52,XX,+18) in skin fibroblast cells. The X- and 18-trisomies were derived from a doubling of the mother's chromosomes in early embryonic cell division, and the reciprocal translocation likely developed in the bone marrow of the offspring, considering that it was observed only in blood cells. Such occurrence of trisomies in hybrid individuals is a unique finding in placental mammals.

Histocytological specificities of adrenal cortex in the New World Monkeys, Aotus lemurinus and Saimiri boliviensis

The New World monkey Aotus spp. (night monkeys) are expected for use of valuable experimental animal with the close species of Saimiri spp. (squirrel monkeys). Saimiri is known to show spontaneous hypercortisolemia, although few reports in Aotus. We compared basic states of blood steroid hormones and histological structure of the adrenal glands in two monkeys. Serum cortisol and ACTH levels were statistically lower in Aotus than Saimiri. Conversely, Aotus adrenocortical area showed significant enlargement, especially at the zona fasciculata. Electron microscopic observation at Aotus fasciculata cells revealed notable accumulation of large lipid droplets and irregular shapes of the mitochondrial cristae. These results suggest potential differences in cellular activities for steroidogenesis between Aotus and Saimiri and experimental usefulness in adrenocortical physiology and pathological models.

Multiple sex chromosome systems in howler monkeys (Platyrrhini, Alouatta)

In light of the multiple sex chromosome systems observed in howler monkeys (Alouatta Lacépède, 1799) a combined cladistic analysis using chromosomal and molecular characters was applied to discuss the possible origin of these systems. Mesoamerican and South American howlers were karyologically compared. FISH analysis using the chromosome painting probes for the #3 and #15 human chromosomes was applied to corroborate the homeology of the sexual systems. We found that the HSA3/15 syntenic association, present in the sex chromosome systems of South American Howlers, is not present in those of Mesoamerican ones. The autosomes involved in the translocation that formed the sexual systems in the Mesoamerican and South American species are different, thus suggesting an independent origin. Parsimony analysis resolved the phylogenetic relationships among howler species, demonstrating utility of the combined approach. A hypothesis for the origin of the multiple sex chromosome systems for the genus is proposed.

Chromosome evolution in new world monkeys (Platyrrhini)

During the last decades, New World monkey (NWM, Platyrrhini, Anthropoideae) comparative cytogenetics has shed light on many fundamental aspects of genome organisation and evolution in this fascinating, but also highly endangered group of neotropical primates. In this review, we first provide an overview about the evolutionary origin of the inferred ancestral NWM karyotype of 2n = 54 chromosomes and about the lineage-specific chromosome rearrangements resulting in the highly divergent karyotypes of extant NWM species, ranging from 2n = 16 in a titi monkey to 2n = 62 in a woolly monkey. Next, we discuss the available data on the chromosome phylogeny of NWM in the context of recent molecular phylogenetic analyses. In the last part, we highlight some recent research on the molecular mechanisms responsible for the large-scale evolutionary genomic changes in platyrrhine monkeys.

A comparative study of the recombination pattern in three species of Platyrrhini monkeys (primates)

Homologous chromosomes exchange genetic information through recombination during meiotic synapsis, a process that increases genetic diversity and is fundamental to sexual reproduction. Meiotic studies in mammalian species are scarce and mainly focused on human and mouse. Here, the meiotic recombination events were determined in three species of Platyrrhini monkeys (Cebus libidinosus, Cebus nigritus and Alouatta caraya) by analysing the distribution of MLH1 foci at the stage of pachytene. Moreover, the combination of immunofluorescence and fluorescent in situ hybridisation has enabled us to construct recombination maps of primate chromosomes that are homologous to human chromosomes 13 and 21. Our results show that (a) the overall number of MLH1 foci varies among all three species, (b) the presence of heterochromatin blocks does not have a major influence on the distribution of MLH1 foci and (c) the distribution of crossovers in the homologous chromosomes to human chromosomes 13 and 21 are conserved between species of the same genus (C. libidinosus and C. nigritus) but are significantly different between Cebus and Alouatta. This heterogeneity in recombination behaviour among Ceboidea species may reflect differences in genetic diversity and genome composition.