Sex Behaviour and Sex Determination in Crepidula Fornicata L

1959 ◽  
Vol 36 (1) ◽  
pp. 34-39
Author(s):  
JAN Z. WILCZYNSKI
Keyword(s):  
Sex Ratio ◽  
Sex Determination ◽  
Sea Water ◽  
Male And Female ◽  
Crepidula Fornicata ◽  
Naturally Occurring ◽  
Significant Tendency ◽  
Males And Females

1. The percentages of males and females in naturally occurring chains of Crepidula fornicata L. were found to be 39% females, 6% ‘transients’ and 55% males. 2. Disconnected males kept in cages in sea water for 9 months re-established the normal sex ratio. 3. Disconnected males were kept for periods of 4-6 weeks at temperatures of 30° and 10° C. No significant tendency to change sex was observed. 4. Males were injected with extracts of females. No tendency to change sex was observed. 5. In animals of all sizes from small males to large females both male and female gametes are invariably present together. The gametes of both sexes are polymorphic.

scholarly journals Sex determination in crayfish: are intersex Cherax quadricarinatus (Decapoda, Parastacidae) genetically females?

2003 ◽  
Vol 82 (2) ◽  
pp. 107-116 ◽  
Author(s):  
S. PARNES ◽  
I. KHALAILA ◽  
G. HULATA ◽  
A. SAGI
Keyword(s):  
Sex Ratio ◽  
Sex Determination ◽  
Genetic Basis ◽  
Male And Female ◽  
Cherax Quadricarinatus ◽  
Male Ratio ◽  
Males And Females ◽  
Normal Males ◽  
Red Claw Crayfish ◽  
Female Genital

In the Australian red-claw crayfish Cherax quadricarinatus (von Martens) (Decapoda, Parastacidae), a gonochoristic species, seven different combinations of intersex individuals (with both male and female genital openings) have been described. However, to date, the genetic basis for this phenomenon has not been investigated. This study was designed to test a simple chromosome-based sex-determination model for C. quadricarinatus that assumes the male to be the homogametic (ZZ) sex. According to our model, intersex individuals that are functionally males are genetically females (WZ). Individual crosses were performed between intersex and female crayfish, with control crosses being performed between normal males and females. The control crosses yielded, in most cases, the expected 1[ratio ]1 sex ratio in the F1 progeny. Crosses between intersex individuals and females yielded a 1[ratio ]3 (male[ratio ]female) sex ratio in most crosses. According to our hypothesis, one-third of the females produced in a cross of a female with an intersex animal should be WW females. The hypothesis was tested by crossing normal males with F1 females, which were progeny of intersex fathers. These crosses yielded almost 100% females, a finding that conforms to the above-suggested sex determination model for C. quadricarinatus and the female WZ genotype of intersex individuals.

scholarly journals Analysis of the sex ratio in Bradysia matogrossensis (Diptera, Sciaridae)

2000 ◽  
Vol 23 (1) ◽  
pp. 97-103 ◽  
Author(s):  
Lincoln S. Rocha ◽  
André Luiz P. Perondini
Keyword(s):  
Sex Ratio ◽  
Sex Determination ◽  
X Chromosome ◽  
Control Mechanism ◽  
Sex Ratios ◽  
Laboratory Strain ◽  
Chromosome Elimination ◽  
Common Control ◽  
Males And Females ◽  
Successive Generations

In sciarid flies, the control of sex determination and of the progeny sex ratio is exercised by the parental females, and is based on differential X-chromosome elimination in the initial stages of embryogenesis. In some species, the females produce unisexual progenies (monogenic females) while in others, the progenies consist of males and females (digenic females). The sex ratio of bisexual progenies is variable, and departs considerably from 1:1. Bradysia matogrossensis shows both monogenic and digenic reproduction. In a recently established laboratory strain of this species, 15% of the females were digenic, 10% produced only females, 13% produced only males, and 62% produced progenies with one predominant sex (33% predominantly of female and 29% predominantly male progenies). These progeny sex ratios were maintained in successive generations. Females from female-skewed progenies yielded female- and male-producing daughters in a 1:1 ratio. In contrast, daughters of females from male-skewed progenies produce bisexual or male-skewed progenies. The X-chromosome of B. matogrossensis shows no inversion or other gross aberration. These results suggest that the control of the progeny sex ratio (or differential X-chromosome elimination) involves more than one locus or, at least, more than one pair of alleles. The data also suggest that, in sciarid flies, monogeny and digeny may share a common control mechanism.

scholarly journals A molecular genetic approach for sex determination on helmeted hornbill (Rhinoplax vigil) casque: a forensic casework

2020 ◽  
Vol 19 ◽  
pp. 00020
Author(s):  
Yuli S. Fitriana ◽  
Mohammad Irham ◽  
Hari Sutrisno ◽  
Abinawanto
Keyword(s):  
Sex Determination ◽  
Molecular Genetic ◽  
Independent Sets ◽  
Black Market ◽  
Critically Endangered ◽  
Genetic Approach ◽  
Genetic Sexing ◽  
Male And Female ◽  
Forensic Casework ◽  
Males And Females

Helmeted Hornbill (Rhinolax vigil) is the only hornbill that equipped with solid casque made from keratin for both males and females. The demand for casque in the black market was huge and resulted in IUCN status leaped up from vulnerable to critically endangered. We received a total of 68 confiscated helmeted hornbill casques. As part of the casework and the objectives of the study, we determined to reveal the sex status of those casques and the best methods to work with keratinous material. Molecular methods to determining sex in birds rely on the CHD gene located on male and female chromosomes ZZ and ZW, respectively. We optimized laboratory protocols for genetic sexing using three independent sets of primers P2/P8, 2550F/2718R, and CHD1F/CHD1R to amplify regions of the sexlinked CHD-Z and CHD-W genes. The CHD1F/CHD1R determined sex 80.88% of samples. The 2550F/2718R were quite successful, sexing 51.47% of samples. In contrast, the P2/P8 only identified the sex around 20.58% of samples. These results showed that CHD1F/CHD1R works the most effective for sexing the casques with 52.9% females, 27.9% males, and 19.1% unidentified. Therefore, the most accurate and suitable primers are CHD1F/CHD1R, 2550F/2718R, and P2/P8, respectively for keratinous samples.

Routine Infanticide by Married Couples? An Assessment of Baptismal Records from Seventeenth Century Parma

2011 ◽  
Vol 15 (6) ◽  
pp. 507-530 ◽  
Author(s):  
Laura Hynes
Keyword(s):  
Seventeenth Century ◽  
Sex Ratio ◽  
Economic Status ◽  
Married Couples ◽  
Sex Ratio At Birth ◽  
Male And Female ◽  
Socio Economic Status ◽  
Rural And Urban ◽  
Italian City ◽  
Males And Females

Abstract This study uses baptismal records from the Italian city of Parma from 1609 to 1637 to chart the sex ratio of male and female infants at baptism. This article measures the Parman sex ratio against the natural sex ratio at birth for live-born infants, as determined by Praven Visaria, and offers preliminary findings that indicate that married couples used infanticide as a means of controlling family size and sex in seventeenth-century Parma. The 28 years studied encompass both relatively strong economic and agricultural years as well as a variety of crises. By selecting a period with both good and bad economic years it is possible to see if parents behaved differently as their household conditions varied. Further, dividing the approximately 30,000 baptisms by rural and urban jurisdictions and familial socio-economic status makes visible parental recourse to infanticide through unnatural ratios of males and females within different segments of society.

scholarly journals Investigating the interaction between inter-locus and intra-locus sexual conflict using hemiclonal analysis in Drosophila melanogaster

2021 ◽  
Author(s):  
Manas Geeta Arun ◽  
Tejinder Singh Chechi ◽  
Rakesh Meena ◽  
Shradha Dattaraya Bhosle ◽  
Srishti ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Sex Ratio ◽  
Genetic Correlation ◽  
Empirical Evidence ◽  
Sexual Conflict ◽  
Genetic Basis ◽  
Operational Sex Ratio ◽  
Female Fitness ◽  
Male And Female ◽  
Males And Females

Divergence in the evolutionary interests of males and females leads to sexual conflict. Traditionally, sexual conflict has been classified into two types: inter-locus sexual conflict (IeSC) and intra-locus sexual conflict (IaSC). IeSC is modeled as a conflict over outcomes of intersexual reproductive interactions mediated by loci that are sex-limited in their effects. IaSC is thought to be a product of selection acting in opposite directions in males and females on traits with a common underlying genetic basis. While in their canonical formalisms IaSC and IeSC are mutually exclusive, there is growing support for the idea that the two may interact. Empirical evidence for such interactions, however, is limited. Here, we investigated the interaction between IeSC and IaSC in Drosophila melanogaster. Using hemiclonal analysis, we sampled 39 hemigenomes from a laboratory-adapted population of D. melanogaster. We measured the contribution of each hemigenome to adult male and female fitness at three different intensities of IeSC, obtained by varying the operational sex-ratio. Subsequently, we estimated the intensity of IaSC at each sex-ratio by calculating the intersexual genetic correlation for fitness and the proportion of sexually antagonistic fitness-variation. Our results indicate a statistically non-significant trend suggesting that increasing the strength of IeSC ameliorates IaSC in the population.

scholarly journals Nesfatin-1 suppresses fish reproductive axis and gonadal steroidogenesis

Reproduction ◽  
2020 ◽  
Vol 160 (3) ◽  
pp. 445-454
Author(s):  
Jithine Jayakumar Rajeswari ◽  
Suraj Unniappan
Keyword(s):  
Mrna Expression ◽  
Pituitary Hormones ◽  
Reproductive Hormones ◽  
Male And Female ◽  
Beneficial Effects ◽  
Naturally Occurring ◽  
Reproductive Axis ◽  
Brain Aromatase ◽  
Males And Females ◽  
Cytochrome P450 Family

Nesfatin-1 is a naturally occurring orphan ligand in fish and mammals. Research in our lab resulted in the identification of an inhibitory role for nesfatin-1 on pituitary hormones (goldfish) and oocyte maturation (zebrafish). The present study is an extension of these original findings and aimed to determine whether nesfatin-1 has any additional effects on HPG genes in male and female goldfish. We found that a single i.p. injection of synthetic nesfatin-1 (50 ng/g body weight) downregulated the expression of salmon gonadotropin-releasing hormone (sgnrh), chicken gnrh-II (cgnrh-II), kisspeptin receptor (gpr54a) and brain aromatase (cyp19a1b) mRNAs in the hypothalamus of both male and female goldfish at 15 min post-administration. In the pituitary of both males and females, nesfatin-1 reduced luteinizing hormone beta (lhβ) and follicle stimulating hormone beta (fshβ) mRNA expression at 60 min and gpr54a mRNA at 15 min. Similarly, the gonadotropin receptors lhr and fshr were downregulated in the gonads. Meanwhile, gonadotropin inhibiting hormone (gnih), gnih receptor, kisspeptin 1 (kiss1) and gpr54a mRNA expression in the gonads were increased post-nesfatin-1 treatment. Nesfatin-1 negatively influences the star, cytochrome P450 family 11 subfamily A member 1, anti-mullerian hormone and aromatase mRNAs. In agreement with these results, nesfatin-1 reduced plasma estradiol and testosterone in female and male goldfish circulation at 60 min post-injection. The information generated through this research further solidified nesfatin-1 as an inhibitor of reproductive hormones in fish. Targeting nesfatin-1 and related peptides could yield beneficial effects in fish reproduction and aquaculture.

scholarly journals PERBANDINGAN JENIS KELAMIN DAN DIMORFISME SEKSUAL PADA PERTUMBUHAN IKAN GURAMI (Osphronemus goramy) SERTA IMPLIKASINYA TERHADAP STRATEGI SELEKSINYA

2017 ◽  
Vol 11 (4) ◽  
pp. 307 ◽  
Author(s):  
Sularto Sularto ◽  
Rita Febrianti ◽  
Suharyanto Suharyanto
Keyword(s):  
Sex Ratio ◽  
Standard Length ◽  
Adult Size ◽  
Male Fish ◽  
Male And Female ◽  
Fish Breeding ◽  
Significant Difference ◽  
Different Populations ◽  
Males And Females ◽  
Number Of Males

Ikan gurami (Osphronemus goramy Lac.) pada ukuran dewasa memiliki bentuk morfometrik yang khas khususnya pada ikan jantan, sehingga dapat dibedakan antara ikan jantan dan betina. Ikan gurami jantan memiliki dahi menonjol dan bibir tebal. Penelitian ini bertujuan untuk mengevaluasi rasio kelamin dan perbedaan performa pertumbuhan antara jantan dan betina. Ikan uji yang digunakan adalah empat populasi ikan gurami yang berbeda yaitu: Kalimantan Selatan, Jambi, Majalengka, dan Tasikmalaya. Penelitian dilaksanakan di Balai Penelitian Pemuliaan Ikan (BPPI), Sukamandi pada bulan Juni 2014 sampai dengan bulan Juli 2015. Hewan uji yang digunakan adalah benih ikan gurami keturunan galur murni berasal dari Kalimantan Selatan, Jambi (strain Batanghari), Majalengka, dan Tasikmalaya. Perawatan telur, pemeliharaan benih, dan pembesaran menggunakan prosedur operasional standar BPPI tentang pemeliharaan ikan gurami. Pemeliharaan ikan gurami dilakukan selama 14 bulan. Hasil penelitian menunjukkan bahwa berdasarkan jenis kelaminnya jumlah ikan gurami betina (67,3%-80,7%) lebih banyak dibandingkan dengan jumlah jantannya (19,3%-32,7%). Setelah mencapai ukuran > 300 g terdapat perbedaan pertumbuhan antara ikan jantan dan betina (P<0,05) yakni jantan tumbuh lebih cepat dibandingkan betina pada semua populasi yakni berkisar antara 4,74%-5,67% untuk karakter panjang standar, dan 14,10%-16,52% untuk karakter bobot. Hal tersebut menunjukkan bahwa ikan gurami memiliki dimorfisme pertumbuhan. Oleh karena itu, ketika dilakukan seleksi berdasarkan pertumbuhan 10% terbaik didapatkan ikan jantan 55%-80% lebih banyak dibandingkan ikan betina (20%-45%).Adult size of giant gouramy (Osphronemus goramy, Lac.) has a distinctive shape of morphometric particularly in male fish, making it easy to distinguish between male and female fishes. Giant gouramy males have a prominent forehead and thick lips. This study aimed to determine sex ratios and differences in growth performance between males and females. This study used 4 progenies of giant gouramy seed from four different populations, namely: Kalimantan, Jambi, Majalengka, and Tasikmalaya, aged 14 months. Eggs incubations,seed maintenance and grow-out were conducted using Standard Operational Procedures of Research Institute for Fish Breeding (RIFB) about the rearing of giant gouramy. Seed rearing were carried out for 14 months. The results showed that, based upon the sex ratio, the number of female was more than the number of males, contituting females 67.3%–80.7% and males from 19.3% to 32.7% of populations. After reaching the size of > 300 g there were a significant difference in growth between males and females (P <0.05), in which males grew faster than females in all populations between 4.74%–5.67% for the standard length and 14.10%–16.52% for the weight characters. IThis result indicated that giant gouramy have growth dimorphism.Therefore, when the selection conducted based on the best growth of top 10%, it was found that the number of male composing 55%–80% was higher than the number of female which only accounted for 20%–45%.

scholarly journals PERTUMBUHAN, FAKTOR KONDISI, DAN BEBERAPA ASPEK REPRODUKSI IKAN LEMURU (Amblygaster sirm, Walbaum 1792) DI PERAIRAN SELAT SUNDA

2017 ◽  
Vol 9 (1) ◽  
pp. 43
Author(s):  
Nidya Kartini ◽  
Mennofatria Boer ◽  
Ridwan Affandi
Keyword(s):  
Sex Ratio ◽  
Condition Factor ◽  
Growth Parameters ◽  
Sampling Technique ◽  
Biological Information ◽  
Male And Female ◽  
Conservation Measure ◽  
Males And Females ◽  
First Maturity ◽  
Size At First Maturity

Ikan lemuru (Amblygaster sirm) merupakan salah satu komiditas utama di Selat Sunda yang menjadi target nelayan di Pelabuhan Perikanan Pantai Lebuan. Informasi biologi dibutuhkan untuk menyusun langkah konservasi ikan lemuru. Penelitian ini bertujuan untuk menganalisis kondisi biologis ikan lemuru di perairan Selat Sunda melalui pengkajian parameter pertumbuhan, faktor kondisi, dan beberapa aspek reproduksi. Pengambilan ikan contoh dilakukan pada bulan April-Agustus 2015 dari hasil tangkapan nelayan yang didaratkan di PPP Labuan, Banten menggunakan teknik Penarikan Contoh Acak Berlapis. Jumlah ikan contoh yang diambil selama penelitian sebanyak 527 ekor ikan jantan dan 245 ekor ikan betina. Hasil penelitian menunjukkan bahwa pola pertumbuhan ikan lemuru jantan dan betina adalah isometrik, nilai faktor kondisi ikan lemuru jantan berkisar 0,9346 – 1,0294 dan betina berkisar 0,9401 – 1,0738, parameter pertumbuhan L∞, K, dan t0 pada ikan jantan adalah 248,80 mm; 0,24/tahun;dan -0,38. Adapun parameter (L∞, K, dan t0) pada ikan betina adalah 235,26 mm; 0,46/tahun, dan -0,20. Nisbah kelamin ikan lemuru jantan dan betina TKG IV adalah 0,75:1. Ukuran pertama kali matang gonad (Lm) ikan lemuru jantan dan betina adalah 188 mm dan 186 mm. Sedangkan ukuran pertama kali tertangkap (Lc) ikan lemuru jantan dan betina adalah 172 mm dan 173 mm. Musim pemijahan ikan lemuru diduga terjadi pada bulan Mei dan Juli.The spotted sardinella (Amblygaster sirm) was one of main commodities in the Sunda Strait that maily targeted by fishers in Labuan Coastal Fishing Port, Banten. The biological  information  needed to setup conservation measure of the spotted sardinella. This research aims to analyse the biological conditions of spotted sardinella in the Sunda Strait by reviewing parameters of growth, condition factor, and some reproduction aspect. Research was conducted in April-August 2015 in Labuan Coastal Fishing Port, Banten by using Random Stratified Sampling technique. About 700 samples (527 male and 245 female fishes) collected during study. The results showed that the growth pattern of male and female were isometric, value of condition factor for male ranged from 0,9346 – 1,0294 and for female ranged from 0,9401 – 1,0738. The estimated growth parameters (L∞, K, and t0) for male were 248,80 mm; 0,24 year-1;and -0,38 respectively. While, the parameters (L∞, K, and t0) of female were 235,26 mm; 0,46 year-1;and -0,20 respectively. The sex ratio between males and females for spotted sardinella was 0,75:1. The size at first maturity (Lm) of male and female were 188 mm and 186 mm, respectively. In addition, the size a first caught (Lc) of male and female was 172 mm and 173 mm, respectively. Thespawning season spotted sardinella possibly occurs in May and July.

scholarly journals Haploid selection, sex ratio bias, and transitions between sex-determining systems

2018 ◽  
Author(s):  
Michael Francis Scott ◽  
Matthew Miles Osmond ◽  
Sarah Perin Otto
Keyword(s):  
Sex Ratio ◽  
Sex Determination ◽  
Sex Chromosomes ◽  
Pollen Competition ◽  
Diploid Males ◽  
Mendelian Segregation ◽  
Male And Female ◽  
Ratio Bias ◽  
Sex Ratio Bias ◽  
Haploid Selection

AbstractSex determination is remarkably dynamic; many taxa display shifts in the location of sex-determining loci or the evolution of entirely new sex-determining systems. Predominant theories for why we observe such transitions generally conclude that novel sex-determining systems are favoured by selection if they equalise the sex ratio or increase linkage with a locus that experiences different selection in males vs. females. We use population genetic models to extend these theories in two ways: (1) We consider the dynamics of loci very tightly linked to the ancestral sex-determining loci, e.g., within the non-recombining region of the ancestral sex chromosomes. Variation at such loci can favour the spread of new sex-determining systems in which the heterogametic sex changes (XY to ZW or ZW to XY) and the new sex-determining region is less closely linked (or even unlinked) to the locus under selection. (2) We consider selection upon haploid genotypes either during gametic competition (e.g., pollen competition) or meiosis (i.e., non-Mendelian segregation), which can cause the zygotic sex ratio to become biased. Haploid selection can drive transitions between sex-determining systems without requiring selection to act differently in diploid males vs. females. With haploid selection, we find that transitions between male and female heterogamety can evolve where linkage with the sex-determining locus is either strengthened or weakened. Furthermore, we find that sex-ratio biases may increase or decrease with the spread of new sex chromosomes, which implies that transitions between sex-determining systems cannot be simply predicted by selection to equalise the sex ratio. In fact, under many conditions, we find that transitions in sex determination are favoured equally strongly in cases where the sex ratio bias increases or decreases. Overall, our models predict that sex determination systems should be highly dynamic, particularly when haploid selection is present, consistent with the evolutionary lability of this trait in many taxa.Author summarySystems of sex determination are strikingly diverse and labile in many clades. This poses the question: what drives transitions between sex-determining systems? Here, we use models to derive conditions under which new sex-determining systems spread. Prevailing views suggest that new sex-determining systems are favoured when they equalize the sex ratio and/or when they are more closely linked to genes that experience differential selection in males and females. Our models include selection upon haploid genotypes (meiotic drive or gametic competition), which biases the sex-ratio and occurs differently in male and female gametes. Surprisingly, we find the two forces (selection to equalize the sex ratio and the benefits of hitchhiking alongside driven alleles that distort the sex ratio) will often be equally strong, and thus neither is sufficient to explain the spread of new sex-determining systems in every case. We also find that new sex-determining alleles can spread despite being less closely linked to selected loci as long as initial linkage is tight or haploid selection is present. Our models therefore predict that loci in previously unexpected genomic locations and/or experiencing various types of selection (including haploid selection) can now be implicated as drivers of transitions between sex-determining systems.

Chromatin dynamics associated with sexual differentiation in a UV sex determination system

2020 ◽  
Author(s):  
Josselin Gueno ◽  
Simon Bourdareau ◽  
Guillaume Cossard ◽  
Olivier Godfroy ◽  
Agnieszka Lipinska ◽  
...  
Keyword(s):  
Gene Expression ◽  
Sex Determination ◽  
Histone Modifications ◽  
Sex Chromosomes ◽  
Sexual Differentiation ◽  
Chromatin State ◽  
State Transitions ◽  
Male And Female ◽  
Chromatin States ◽  
Males And Females

SummaryIn many eukaryotes, such as dioicous mosses and many algae, sex is determined by UV sex chromosomes and is expressed during the haploid phase of the life cycle. In these species, the male and female developmental programs are initiated by the presence of the U- or V-specific regions of the sex chromosomes but, as in XY and ZW systems, phenotypic differentiation is largely driven by autosomal sex-biased gene expression. The mechanisms underlying sex-biased transcription in XY, ZW or UV sexual systems currently remain elusive. Here, we set out to understand the extent and nature of epigenomic changes associated with sexual differentiation in the brown alga Ectocarpus, which has a well described UV system. Five histone modifications, H3K4me3, H3K27Ac, H3K9Ac, H3K36me3, H4K20me3, were quantified in near-isogenic male and female lines, leading to the identification of 13 different chromatin states across the Ectocarpus genome that showed different patterns of enrichment at transcribed, silent, housekeeping or narrowly-expressed genes. Chromatin states were strongly correlated with levels of gene expression indicating a relationship between the assayed marks and gene transcription. The relative proportion of each chromatin state across the genome remained stable in males and females, but a subset of genes exhibited different chromatin states in the two sexes. In particular, males and females displayed distinct patterns of histone modifications at sex-biased genes, indicating that chromatin state transitions occur preferentially at genes involved in sex-specific pathways. Finally, our results reveal a unique chromatin landscape of the U and V sex chromosomes compared to autosomes. Taken together, our observations reveal a role for histone modifications in sex determination and sexual differentiation in a UV sexual system, and suggest that the mechanisms of epigenetic regulation of genes on the UV sex chromosomes may differ from those operating on autosomal genes.

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