Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “HERMAPHRODITISM”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1990

Sexuality and hermaphroditism in fishes. I. Synchronous functional hermaphroditism in the serranid fish Serranus scriba L.

Anatomical and histological examination of Serranus scriba L. showed the existence of primary females (67%), hermaphrodites (31%) and primary males (2%). Synchronous functional hermaphroditism is described on the basis of an anatomical and histological study of the gonads. Although they function simultaneously, the testicular and ovarian parts of hermaphrodite gonads have completely separate ducts. Females and hermaphrodites have the same annual reproduction cycle. In hermaphrodites, the testicular part matures one month sooner than the ovarian part. Cross fertilization between primary females and hermaphrodite individuals and between two different hermaphrodites probably occurs, while self-fertilization is less likely. The testicular tissues of primary males are of the acinar type and those of hermaphrodites are of the radial type. It is possible that primary males do not take part in reproduction. Serranus scriba in Egyptian Mediterranean waters is a longperiod spawner, which spawns from June to the end of October, i.e. it is a summer-autumn spawner.

Animals↗
PubMed2003

Simultaneous hermaphrodites reproducing in pairs self-fertilize some of their eggs: an experimental test of predictions of mixed-mating and Hermaphrodite's Dilemma theory.

Theory predicts (1) that mixed-mating systems (i.e. reproduction through both selfing and outcrossing) should usually not evolve and (2) that reproducing simultaneous hermaphrodites should be in a conflict over the preferred sexual role (The Hermaphrodite's Dilemma). In an in vitro system with the endoparasitic cestode Schistocephalus solidus, a simultaneous hermaphrodite, we tested predictions of both the mixed-mating and the Hermaphrodite's Dilemma theory. Using microsatellite markers, we measured the proportion of selfed offspring and the total reproductive output of each worm within pairs varying in mean weight and weight difference. Worms produced more outbred offspring not only with increasing total weight of the pair, but also with decreasing weight difference between the two paired worms. These results suggest: (1) that this parasite species reproduces by mixed-mating, which may be maintained by stochastic density fluctuations in the definitive host and hence unpredictability of self reproduction and (2) reproductive conflict may prevent worm pairs from achieving an optimal intermediate selfing rate.

Animals↗
PubMed1993

Familial true hermaphroditism: paternal and maternal transmission of true hermaphroditism (46,XX) and XX maleness in the absence of Y-chromosomal sequences.

We report on 46,XX true hermaphroditism and 46,XX maleness coexisting in the same pedigree, with maternal as well as paternal transmission of the disorder. Molecular genetic analysis showed that both hermaphrodites as well as the 46,XX male were negative for Y-chromosomal sequences. Thus, this pedigree is highly informative and allows the following conclusions: first, the maternal as well as paternal transmission of the disorder allows the possibility of an autosomal dominant as well as an X-chromosomal dominant mode of inheritance; second, testicular determination in the absence of Y-specific sequences in familial 46,XX true hermaphrodites as well as in 46,XX males seems to be due to the varying expression of the same genetic defect; and third, there is incomplete penetrance of the defect.

Adult↗
PubMed1998

The cost of sex revisited: effects of male gamete output of hermaphrodites that are asexual in their female capacity.

The genetic cost of sexual reproduction has been attributed to two causes in mathematical formulations: male function or genome dilution. We develop and analyse a genetic model that shows that both costs occur, depending upon the conditions. The model differs from previous formulations in that the level of output and fertilization success of male gametes produced by hermaphrodites that are asexual in their female function (henceforth "parthenogenetic hermaphrodites") are treated as variables, rather than constants fixed at 0 or 1, as has previously been the case. By expressing the cost of sex in terms of per capita egg loss of sexual individuals and parthenogenetic hermaphrodites, we partition the cost into components due to male function and genome dilution. Which component dominates the cost of sex depends upon the relative male gamete output of the parthenogenetic hermaphrodites. The cost of sex is observed to increase, or remain unchanged in some marginal cases, with increases in (i) frequency of parthenogenetic hermaphrodites, (ii) fertilization success of male gametes produced by parthenogenetic hermaphrodites and (iii) potential eggs lost by diverting resources to male gamete production. In certain situations, parthenogenetic hermaphrodites with an intermediate level of male gamete output have the greatest fitness advantage over sexual individuals. If heritable variation for levels of male gamete output exists among parthenogenetic hermaphrodites, this raises the possibility of the evolution of optimal levels of male gamete production by parthenogenetic hermaphrodites through natural selection, in situations of recurring invasion of asexual populations by propagules from sexual populations, a scenario that is increasingly being appreciated as potentially fairly likely to occur in nature.

Animals↗
PubMed2006

Genetic flexibility in the convergent evolution of hermaphroditism in Caenorhabditis nematodes.

The self-fertile hermaphrodites of C. elegans and C. briggsae evolved from female ancestors by acquiring limited spermatogenesis. Initiation of C. elegans hermaphrodite spermatogenesis requires germline translational repression of the female-promoting gene tra-2, which allows derepression of the three male-promoting fem genes. Cessation of hermaphrodite spermatogenesis requires fem-3 translational repression. We show that C. briggsae requires neither fem-2 nor fem-3 for hermaphrodite development, and that XO Cb-fem-2/3 animals are transformed into hermaphrodites, not females as in C. elegans. Exhaustive screens for Cb-tra-2 suppressors identified another 75 fem-like mutants, but all are self-fertile hermaphrodites rather than females. Control of hermaphrodite spermatogenesis therefore acts downstream of the fem genes in C. briggsae. The outwardly similar hermaphrodites of C. elegans and C. briggsae thus achieve self-fertility via intervention at different points in the core sex determination pathway. These findings are consistent with convergent evolution of hermaphroditism, which is marked by considerable developmental genetic flexibility.

Animals↗
PubMed1991

Sex reversing non-disjunction of the Y chromosome produces exceptionally low sex ratio (% males) and hermaphrodites in the progeny of male BALB/cBm mice: the roles of the maternal genotype and the Y chromosome.

When females of 21 strains and hybrids were mated to BALB/cBm males to determine the role of the maternal genome in the sex reversing non-disjunction of the Y chromosome, (1) BALB/cBm and BALB/cBy and SJL/J females produced 39.5-41.5% males and 2.4-2.8% hermaphrodites; (2) SWR/J, A/HeJ, DBA/2J and C3HeB/FeJ produced 44.8-49.1% males and 0.2-0.7% hermaphrodites; (3) C3H/HeJ and three strains of C57BL produced normal sex ratios and no hermaphrodites; (4) four F1 hybrids produced 44.5-49.2% males and 0.3-1.9% hermaphrodites; (5) the seven CXB RI strains produced perplexing sets of data: 26.5%-52.0% males and 0.2-3.2% hermaphrodites. These results indicate that a partly dominant gene favouring non-disjunction occurs in the female genomes of BALB/c and SJL/J strains, an enhancing gene occurs in C57BL/6By and there may be others. Heterosis appears to favour normal mitosis. CXBH females produced 26.5% males and 3.2% hermaphrodites, indicating that non-disjunction may have occurred in every male zygote, thus providing models for the generation of Turner's syndrome, hermaphroditism and a predictable non-disjunction. Reciprocal crosses were made between SJL/J and BALB/cBm, followed by 20 backcrosses to the maternal strains, to exchange the Ys and produce two new consomic strains. Males from SJL-BALB/cBm-Y strain, when mated to CXBH females, sired 34.3% males and 4.3% hermaphrodites, whereas BALB/cBm-SJL-Y sired no hermaphrodites and the sex ratio of the offspring was normal. This shows that the non-disjunction involves only the BALB/cBm Y chromosome and is completely independent of genes on the X or autosomal chromosomes. These results indicate that the BALB/cBm Y chromosome is unable to interact normally with the mitotic spindles of some genotypes, particularly CXBH, BALB/c and SJL. The simplest hypothesis is that a primary non-disjunction occurs at first cleavage. This can produce an array of mosaics determined by chance in the many sampling events that take place during development and by the relative vigour and stability of the two original clones.

Animals↗
PubMedDate not supplied

[Surgical correction of hermaphroditism].

By their documents people worldwide are of male or female gender. But in fact, four genders exist: male, female, hermaphroditism and eunuchoidism. Neonatologists must know how to diagnose minimum three sexual anomalies: true hermaphroditism, false male hermaphroditism and false female hermaphroditism. Such knowledge leads to surgical correction of hermaphroditism early in childhood. Six criteria of sex diagnosis is described: chromosomal (genetic) sex; gonadal (true) sex; hormonal sex; phenotypical (somatic) sex; psychological sex; legal sex. Variants of false male, false female and true hermaphroditism, principles of surgical correction of hermaphroditism are outlined. 3 true hermaphrodits are described. A 22-year-old and 13-year-old true hermaphrodits were operated to be a male and female, respectively. Sex correction is based on the patient's and his parents' will. This will, as a rule, coincides with a legal sex documented in the maternity home and sexual psychoorientation obtained from the associates.

Adolescent↗
PubMed2006

Hermaphroditism: What's not to like?

Hermaphroditism is rare and phylogenically in decline among animal species. The evolutionary basis for this development is not well understood. This paper focusses on self-incompatible simultaneous hermaphroditism in animals. It proposes that such hermaphroditism is not stable in sufficiently heterogeneous populations, suggesting a possible reason for why hermaphroditism is rare among evolved animal species. The argument turns on the Bateman principle, namely that male reproductive success (RS) is limited by partner availability, while female RS is not. We show that: low-quality individuals do better if female; secondary sexual differentiation may be important for understanding the existence of males; and that hermaphroditic mating is reciprocal. Reciprocity may be key to understanding promiscuity and attendant phenomena such as cryptic female choice, sperm competition and love darts-common features of hermaphroditic mating. We also argue that hermaphrodites are especially vulnerable to male violence, suggesting a reason for the rarity of trioecy. Finally, we propose that external fertilization, and the scope for streaking, may be one reason fish are the only simultaneously hermaphroditic vertebrates.

Animals↗
PubMed2006

Testing three models on the adaptive significance of protandric simultaneous hermaphroditism in a marine shrimp.

Protandric simultaneous hermaphroditism, as reported for shrimps in the genus Lysmata, is a sexual system in which individuals invariably reproduce as males first and later in life as simultaneous hermaphrodites. I tested three models (i.e., sex-dependent energetic costs, sex-dependent mortality rates and sex-dependent time commitments) in an attempt to explain the adaptive value of protandric simultaneous hermaphroditism in the shrimp L. wurdemanni. Specific assumptions and predictions of each model were evaluated using manipulative experiments. In the laboratory, males grew faster than simultaneous hermaphrodites of the same size and age, an indication that the female function incurs higher energetic costs of reproduction than the male function. Also, large SHPs were more successful in monopolizing food than small males. The sex-dependent growth rate and size-dependent resource holding power agree with predictions of the sex-dependent energetic cost model. The time that simultaneous hermaphrodites required for replenishing their sperm reservoirs after mating as males was much shorter (2 days) than the time required to brood one clutch of embryos (11 days). Also, small simultaneous hermaphrodites experienced heavier mortality due to predatory fishes than large ones. The sex-dependent reproductive time commitment and size-dependent mortality agree with predictions of the sex-dependent time commitment model. Conversely, I found no evidence that the sex-dependent mortality model explains protandric simultaneous hermaphroditism in the studied species. In contrast to model predictions, mortality due to predatory fishes suffered by simultaneous hermaphrodites was not greater than that suffered by males of the same body size. In L. wurdemanni, the relationship between sex-specific investment and reproductive success seems to change during ontogeny in a way that is consistent with an adaptive adjustment of sex allocation to improve age-specific reproductive success.

Adaptation, Physiological↗
PubMed1982

The synaptonemal complexes of Caenorhabditis elegans: pachytene karyotype analysis of male and hermaphrodite wild-type and him mutants.

Only five synaptonemal complexes (SC), representing the 5 autosomes, are present in wild-type, him-4 and him-8, Caenorhabditis elegans males, whereas there are six SCs, accounting for 5 autosomal bivalents and the XX bivalent, in the C. elegans hermaphrodite. The univalent X chromosome of the male is present as a heterochromatic 'X-body' in spermatocyte pachytene nuclei. The XX bivalent in wild-type, him-4 and him-8 hermaphrodites (SC1, 2.5 microns in length) represented 6% of the total karyotype length and a SC of this size is missing from the respective male karyotypes. This corresponds with the fact that the total male karyotype length is only approximately 94% that of the hermaphrodite. Associated with the central element of the SC are structures termed 'SC knobs' that were first described in the wild-type hermaphrodite. The six SC knobs present in the wild-type hermaphrodite oocyte pachytene nuclei and the two SC knobs in the male spermatocyte pachytene nuclei are apparently randomly placed with the exception that they are never found at the ends of the SC. This is also true in him-4 and him-8 in which case there are 3 and zero SC knobs in the hermaphrodites, respectively, and one SC knob each in the male pachytene nuclei. The decrease in number of SC knobs in hermaphrodite to male represents a true sex difference. The presence or absence of the SC knobs may influence the X chromosome nondisjunction process and this effect is not localized to the region of the SC on which the SC knob is located.

Animals↗