The ontogeny of the urogenital system of the spotted hyena (Crocuta crocuta Erxleben). (1/26)Studies were conducted to elucidate the importance of androgen-mediated induction of the extreme masculinization of the external genitalia in female spotted hyenas. Phallic size and shape; androgen receptor (AR) and alpha-actin expression; and sex-specific differences in phallic retractor musculature, erectile tissue, tunica albuginea, and urethra/urogenital sinus were examined in male and female fetuses from Day 30 of gestation to term. Similar outcomes were assessed in fetuses from dams treated with an AR blocker and a 5alpha-reductase inhibitor (antiandrogen treatment). Clitoral and penile development were already advanced at Day 30 of gestation and grossly indistinguishable between male and female fetuses throughout pregnancy. Sex-specific differences in internal phallic organization were evident at Gestational Day 45, coincident with AR expression and testicular differentiation. Antiandrogen treatment inhibited prostatic development in males and effectively feminized internal penile anatomy. We conclude that gross masculinization of phallic size and shape of male and female fetuses is androgen-independent, but that sexual dimorphism of internal phallic structure is dependent on fetal testicular androgens acting via AR in the relevant cells/tissues. Androgens secreted by the maternal ovaries and metabolized by the placenta do not appear to be involved in gross masculinization or in most of the sex differences in internal phallic structure. (+info)
Seroprevalence and genomic divergence of circulating strains of feline immunodeficiency virus among Felidae and Hyaenidae species. (2/26)Feline immunodeficiency virus (FIV) infects numerous wild and domestic feline species and is closely related to human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV). Species-specific strains of FIV have been described for domestic cat (Felis catus), puma (Puma concolor), lion (Panthera leo), leopard (Panthera pardus), and Pallas' cat (Otocolobus manul). Here, we employ a three-antigen Western blot screening (domestic cat, puma, and lion FIV antigens) and PCR analysis to survey worldwide prevalence, distribution, and genomic differentiation of FIV based on 3,055 specimens from 35 Felidae and 3 Hyaenidae species. Although FIV infects a wide variety of host species, it is confirmed to be endemic in free-ranging populations of nine Felidae and one Hyaenidae species. These include the large African carnivores (lion, leopard, cheetah, and spotted hyena), where FIV is widely distributed in multiple populations; most of the South American felids (puma, jaguar, ocelot, margay, Geoffroy's cat, and tigrina), which maintain a lower FIV-positive level throughout their range; and two Asian species, the Pallas' cat, which has a species-specific strain of FIV, and the leopard cat, which has a domestic cat FIV strain in one population. Phylogenetic analysis of FIV proviral sequence demonstrates that most species for which FIV is endemic harbor monophyletic, genetically distinct species-specific FIV strains, suggesting that FIV transfer between cat species has occurred in the past but is quite infrequent today. (+info)
The population history of extant and extinct hyenas. (3/26)We have analyzed partial DNA sequences of the mitochondrial cytochrome b gene from extant striped, brown, and spotted hyenas as well as from Pleistocene cave hyenas. Sequences of the Pleistocene cave hyenas from Eurasia and modern spotted hyenas from Africa are intermixed in phylogenetic analyses, questioning any taxonomic delineation between the two groups. Contrary to cave hyenas in Eurasia, spotted hyenas in Africa show a phylogeographic pattern with little geographical overlap between two mitochondrial DNA (mtDNA) clades, suggesting two Pleistocene refugia in the north and south of Africa. Our results, furthermore, suggest three waves of migration from Africa to Eurasia for spotted hyenas, around 3, 1, and 0.3 MYA. A recent emigration of striped hyenas from Africa to Eurasia took place less than 0.1 MYA, resulting in a dramatic expansion of the geographical range of striped hyenas. In striped hyenas and within the geographical range of mtDNA clades in spotted hyenas, we found identical sequences several thousand kilometers apart, indicating a high rate of migration during the Pleistocene as well as the Holocene. Both striped and brown hyenas show low amounts of genetic diversity, with the latter ones displaying just a single haplotype. (+info)
Estimating relatedness and relationships using microsatellite loci with null alleles. (4/26)Relatedness is often estimated from microsatellite genotypes that include null alleles. When null alleles are present, observed genotypes represent one of several possible true genotypes. If null alleles are detected, but analyses do not adjust for their presence (ie, observed genotypes are treated as true genotypes), then estimates of relatedness and relationship can be incorrect. The number of loci available in many wildlife studies is limited, and loci with null alleles are commonly a large proportion of data that cannot be discarded without substantial loss of power. To resolve this problem, we present a new approach for estimating relatedness and relationships from data sets that include null alleles. Once it is recognized that the probability of the observed genotypes is dependent on the probabilities of a limited number of possible true genotypes, the required adjustments are straightforward. The concept can be applied to any existing estimators of relatedness and relationships. We review established maximum likelihood estimators and apply the correction in that setting. In an application of the corrected method to data from striped hyenas, we demonstrate that correcting for the presence of null alleles affect results substantially. Finally, we use simulated data to confirm that this method works better than two common approaches, namely ignoring the presence of null alleles or discarding affected loci. (+info)
Endocrine differentiation of fetal ovaries and testes of the spotted hyena (Crocuta crocuta): timing of androgen-independent versus androgen-driven genital development. (5/26)Female spotted hyenas (Crocuta crocuta) have an erectile peniform clitoris and a pseudoscrotum but no external vagina, all established by day 35 of a 110-day gestation. Recent studies indicate that these events are androgen-independent, although androgen secretion by fetal ovaries and testis was hypothesized previously to induce phallic development in both sexes. We present the first data relating to the capacity of the ovaries and testes of the spotted hyena to synthesize androgens at different stages of fetal life. Specifically, spotted hyena fetal gonads were examined by immunohistochemistry at GD 30, 45, 48, 65, and 95 for androgen-synthesizing enzymes, as related to the morphological development. Enzymes included 17alpha-hydroxylase/17,20-lyase cytochrome P450 (P450c17), cytochrome b5, 3beta-hydroxysteroid dehydrogenase (3betaHSD), and cholesterol side-chain cleavage cytochrome P450 (P450scc). Anti-Mullerian-hormone (AMH) expression was also examined. AMH was strongly expressed in fetal Sertoli cells from GD 30 and after. P450c17 expression was detected in Leydig cells of developing testes and surprisingly in Mullerian duct epithelium. Fetal ovaries began to organize and differentiate by GD 45, and medullary cells expressed P450c17, cytochrome b5, 3betaHSD, and P450scc. The findings support the hypothesis that external genital morphology is probably androgen-independent initially, but that fetal testicular androgens modify the secondary, male-specific phallic form and accessory organs. Fetal ovaries appear to develop substantial androgen-synthesizing capacity but not until phallic differentiation is complete, i.e. after GD 45 based on circulating androstenedione concentrations. During late gestation, fetal ovaries and testes synthesize androgens, possibly organizing the neural substrates of aggressive behaviors observed at birth in spotted hyenas. These data provide an endocrine rationale for sexual dimorphisms in phallic structure and reveal a potential source of androgenic support for neonatal aggression in female and male C. crocuta. (+info)
Social intelligence in the spotted hyena (Crocuta crocuta). (6/26)If the large brains and great intelligence characteristic of primates were favoured by selection pressures associated with life in complex societies, then cognitive abilities and nervous systems with primate-like attributes should have evolved convergently in non-primate mammals living in large, elaborate societies in which social dexterity enhances individual fitness. The societies of spotted hyenas are remarkably like those of cercopithecine primates with respect to size, structure and patterns of competition and cooperation. These similarities set an ideal stage for comparative analysis of social intelligence and nervous system organization. As in cercopithecine primates, spotted hyenas use multiple sensory modalities to recognize their kin and other conspecifics as individuals, they recognize third-party kin and rank relationships among their clan mates, and they use this knowledge adaptively during social decision making. However, hyenas appear to rely more intensively than primates on social facilitation and simple rules of thumb in social decision making. No evidence to date suggests that hyenas are capable of true imitation. Finally, it appears that the gross anatomy of the brain in spotted hyenas might resemble that in primates with respect to expansion of frontal cortex, presumed to be involved in the mediation of social behaviour. (+info)
Mitochondrial introgressions into the nuclear genome of the domestic cat. (7/26)Translocation of mtDNA into the nuclear genome, also referred to as numt, was first reported in the domestic cat (Felis catus) by Lopez et al. (1994). The Lopez-numt consisted of a translocation of 7.9 kbp of mtDNA that inserted into the domestic cat chromosome D2 around 1.8 million years ago. More than a decade later, the release of the domestic cat whole-genome shotgun sequences (1.9x coverage) provides the resource to obtain more comprehensive insight into the extent of mtDNA transfer over time in the domestic cat genome. MegaBLAST searches revealed that the cat genome harbors a wide variety of numts (298 320 bp), one-third of which likely correspond to the Lopez-numt tandem repeat, whereas the remaining numts are probably derived from multiple independent insertions, which in some cases were followed by segmental duplication after insertion in the nucleus. Numts were detected across most cat chromosomes, but the number of numts assigned to chromosomes is underestimated due to the relatively high number of numt sequences with insufficient flanking sequence to map. The catalog of cat numts provides a valuable resource for future studies in Felidae species, including its use as a tool to avoid numt contaminations that may confound population genetics and phylogenetic studies. (+info)
Non-invasive measurement of fecal estrogens in the spotted hyena (Crocuta crocuta). (8/26)Fecal hormone analysis is a useful tool for frequent, non-invasive sampling of free-living animals. Estrogens fluctuate throughout life among reproductive states in female animals, and intensive repetitive sampling can permit accurate assessment of female reproductive condition. This type of repetitive sampling is difficult in large carnivores, including the spotted hyena (Crocuta crocuta). Patterns of estrogen secretion in captive and free-living hyenas are virtually unknown. Here we present validation of an enzyme-immunoassay to measure fecal estrogen (fE) concentrations in wild and captive spotted hyenas. Results from high-performance liquid chromatography indicate that an antibody specific for estradiol exhibits high immunoreactivity with our extracted samples. Fecal extract displacement curves paralleled our estradiol standard curve within the range of 20-80% antibody binding. Additionally, animals treated with luteinizing hormone-releasing hormone showed a measurable rise in fE concentrations. Finally, once we controlled for effects of time of day of sample collection from wild hyenas, patterns in fE concentrations resembled those in plasma estradiol, including higher levels of fE in mature than immature females, and higher levels of fE during late than early pregnancy. Together, these results suggest that fE concentrations reflect circulating estrogens in spotted hyenas. (+info)
Hyaenidae is not a medical term, but a biological term related to zoology and taxonomy. It refers to the family of mammals that includes hyenas. Hyenas are often mistakenly classified as members of the canid (dog) or felid (cat) families, but they are actually more closely related to herons, eagles, and other members of the order Carnivora.
There are four extant species in the Hyaenidae family: the striped hyena (Hyaena hyaena), the brown hyena (Parahyaena brunnea), the spotted hyena (Crocuta crocuta), and the aardwolf (Proteles cristata). These animals are known for their strong social structures, hunting skills, and powerful jaws.
While Hyaenidae is not directly related to medical terminology, understanding the classification of animals can be important in fields such as epidemiology and public health, where knowledge of animal behavior and ecology can help inform disease surveillance and control efforts.
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- Here, we employ a three-antigen Western blot screening (domestic cat, puma, and lion FIV antigens) and PCR analysis to survey worldwide prevalence, distribution, and genomic differentiation of FIV based on 3,055 specimens from 35 Felidae and 3 Hyaenidae species. (nih.gov)
- Although FIV infects a wide variety of host species, it is confirmed to be endemic in free-ranging populations of nine Felidae and one Hyaenidae species. (nih.gov)
- In this paper we review the collection of fossil carnivores from the late Early Pleistocene site of Cueva Victoria (south-eastern Iberian Peninsula) including the families Ursidae, Hyaenidae and Felidae. (researchgate.net)
- Marmoset Diet Canned is formulated to be fed as the sole diet for non-domestic carnivores in the families Felidae, Canidae and Hyaenidae. (petlewa.com)
- The aardwolf is the smallest member of the hyena family Hyaenidae. (dinosaursrocksuperstore.com)
- The four species of hyena-spotted, striped, brown, and the aardwolf-are their own family (Hyaenidae), but if you back up the taxonomic chain a little to the order Carnivora, you'll see that the hyena family and the mongoose family share their most recent common ancestor. (blogspot.com)
- Instead, they are so unique that they have a family all their own, Hyaenidae. (travelbutlers.com)
- Molecular systematics of the Hyaenidae: Relationships of a relictual lineage resolved by a molecular supermatrix. (procarnivoros.org.br)