scholarly journals Polygenic sex determination produces modular sex polymorphism in an African cichlid fish

2021 ◽  
Author(s):  
Emily C Moore ◽  
Patrick J Ciccotto ◽  
Erin N Peterson ◽  
Melissa S Lamm ◽  
R. Craig Albertson ◽  
...  
Keyword(s):  
Sex Determination ◽  
Genetic Locus ◽  
Cichlid Fish ◽  
Single Species ◽  
Craniofacial Morphology ◽  
Secondary Sexual Characteristics ◽  
Home Tank ◽  
Sexual Characteristics ◽  
Polygenic Sex Determination ◽  
Secondary Sexual

For many vertebrates, a single genetic locus initiates a cascade of developmental sex differences in the gonad and throughout the organism, resulting in adults with two, phenotypically distinct sexes. Species with polygenic sex determination (PSD) have multiple interacting sex determination alleles segregating within a single species, allowing for more than two genotypic sexes, and scenarios where sex genotype at a given locus can be decoupled from gonadal sex. Here we investigate the effects of PSD on secondary sexual characteristics in the cichlid fish Metriaclima mbenjii, where one female (W) and one male (Y) sex determination allele interact to produce siblings with four possible sex classes: ZZXX females, ZWXX females, ZWXY females, and ZZXY males. We find that PSD in M. mbenjii produces an interplay of sex-linkage and sex-limitation resulting in modular variation in morphological and behavioral traits. Further, the evolution or introgression of a novel sex determiner creates additional axes of phenotypic variation for varied traits, including genital morphology, craniofacial morphology, gastrointestinal morphology, and home tank behaviors. In contrast to single-locus sex determination, which broadly results in sexual dimorphism, polygenic sex determination can induce higher-order sexual polymorphism. The modularity of secondary sexual characteristics produced by PSD provides novel context for understanding the evolutionary causes and consequences of maintenance, gain, or loss of sex determination alleles in populations.

Sex determination and Y chromosome constitutive heterochromatin

2019 ◽  
Vol 1 (1) ◽  
pp. 1-5
Author(s):  
Abyt Ibraimov
Keyword(s):  
Sex Determination ◽  
Y Chromosome ◽  
Constitutive Heterochromatin ◽  
Sex Differentiation ◽  
Secondary Sexual Characteristics ◽  
Biological Meaning ◽  
Heterochromatin Block ◽  
Sexual Characteristics ◽  
Open Question ◽  
Efficient Elimination

In many animals, including us, the genetic sex is determined at fertilization by sex chromosomes. Seemingly, the sex determination (SD) in human and animals is determined by the amount of constitutive heterochromatin on Y chromosome via cell thermoregulation. It is assumed the medulla and cortex tissue cells in the undifferentiated embryonic gonads (UEG) differ in vulnerability to the increase of the intracellular temperature. If the amount of the Y chromosome constitutive heterochromatin is enough for efficient elimination of heat difference between the nucleus and cytoplasm in rapidly growing UEG cells the medulla tissue survives. Otherwise it doomed to degeneration and a cortex tissue will remain in the UEG. Regardless of whether our assumption is true or not, it remains an open question why on Y chromosome there is a large constitutive heterochromatin block? What is its biological meaning? Does it relate to sex determination, sex differentiation and development of secondary sexual characteristics? If so, what is its mechanism: chemical or physical? There is no scientifically sound answer to these questions.

Comparative urogenital morphology and external sex determination in muskellunge, Esox masquinongy Mitchill

1989 ◽  
Vol 67 (4) ◽  
pp. 1053-1060 ◽  
Author(s):  
Bernard Lebeau ◽  
Gérard Pageau
Keyword(s):  
Ventral Surface ◽  
Northern Pike ◽  
Structural Basis ◽  
Simple Method ◽  
Esox Masquinongy ◽  
Secondary Sexual Characteristics ◽  
Sexual Characteristics ◽  
Spawning Behaviour ◽  
Accurate Indicator ◽  
Secondary Sexual

Primary and secondary sexual characteristics in northern pike, Esox lucius Linneaus, and muskellunge, Esox masquinongy Mitchill, differ markedly. Differences in the internal urogenital anatomy include the structure of the genital ducts and the angle they form with the ventral surface. Externally, the genital and urinary ducts open directly to the environment in northern pike, whereas in muskellunge they open into a muscular papilla and then through a urogenital pore. Differences in sexual dimorphism between the two closely related esocids constitute a structural basis to explain the known differences in spawning behaviour and reproductive success. Differences in secondary sexual characteristics explain why the methods developed by Demchenko or Casselman to externally sex pike are inapplicable to muskellunge. To develop and test two external sexing techniques for muskellunge, specimens were collected from two regions in Canada from 1980 to 1987. Examination of reproductive products obtained from stripping provided an accurate indicator of sex and sexual maturity, but demonstrated serious limitations. A simple method to sex muskellunge by examination of the external urogenital morphology is described for juveniles and adults. Dissection of fish revealed that with the urogenital examination technique we sexed juveniles with a success rate of 92–98%, and adults with 100% accuracy.

The effects of phthalate and nonylphenol exposure on body size and secondary sexual characteristics during puberty

2015 ◽  
Vol 218 (7) ◽  
pp. 603-615 ◽  
Author(s):  
Jia-Woei Hou ◽  
Ching-Ling Lin ◽  
Yen-An Tsai ◽  
Chia-Huang Chang ◽  
Kai-Wei Liao ◽  
...  
Keyword(s):  
Body Size ◽  
Secondary Sexual Characteristics ◽  
Sexual Characteristics ◽  
Secondary Sexual

scholarly journals Somatotypical features of the age dynamics of secondary sexual characteristics and functional parameters in city schoolchildren

2021 ◽  
pp. 113-118
Author(s):  
V. A. Melnik
Keyword(s):  
Blood Pressure ◽  
Body Type ◽  
Age Dynamics ◽  
Functional Parameters ◽  
Secondary Sexual Characteristics ◽  
Age Related ◽  
Sexual Characteristics ◽  
Age Range ◽  
Age Related Changes ◽  
Secondary Sexual

Objective: to assess the constitutional features of the age dynamics of secondary sexual characteristics and functional parameters of city schoolchildren in the age range of 7–17 years.Materials and methods. The objects of the study were schoolchildren aged 7–17. The stages of the expression of secondary sexual characteristics were determined visually according to the scheme by J.M. Tanner. The functional parameters of the examined schoolchildren were assessed using the methods of dynamometry, spirometry; blood pressure and heart rates, as well as the time of simple sensorimotor reactions were measured.Results. As a result of the performed studies, it has been found that representatives of the hypersomnic types are ahead of other types to reveal the first stages of secondary sexual characteristics. Schoolchildren with the leptosomic morphotypes due to higher rates of their development have reached the definitive stages by the same age as those with the hypersomnic variants. The intensity of age-related changes in functional parameters (strength qualities, circulatory and respiratory systems, nervous system) in the studied objects depends on their body type.Conclusion. The stage and rate of puberty, as well as the development of functional parameters in city schoolchildren depends on their somatotype.

scholarly journals Hypertension, hypokalemia, and left adrenal tumor mimicking primary aldosteronism in a patient with 17α-hydroxylase deficiency

2019 ◽  
Vol 7 (1) ◽  
pp. 6
Author(s):  
Shu-Heng Huang ◽  
Daw-Yang Hwang ◽  
Shang-Jyh Hwang
Keyword(s):  
Primary Aldosteronism ◽  
Adrenal Tumor ◽  
Laboratory Data ◽  
Adrenal Incidentaloma ◽  
Plasma Renin ◽  
Secondary Hypertension ◽  
Hydroxylase Deficiency ◽  
Secondary Sexual Characteristics ◽  
Sexual Characteristics ◽  
Secondary Sexual

17α-hydroxylase deficiency (17OHD) is a rare disorder of secondary hypertension caused by congenital adrenal hyperplasia. In addition, co-occurrence of an adrenal tumor with 17OHD is extremely rare and easily misdiagnosed. A 33-year-old female with sicca syndrome, persistent hypertension, hypokalemia, and a left adrenal tumor was referred for confirmation of primary aldosteronism. However, the absence of secondary sexual characteristics, persistent growth beyond puberty, and laboratory data of low plasma renin activity, high aldosterone, low cortisol, low sex hormones, elevated adrenocorticotropic hormone, elevated luteinizing hormone, elevated follicle-stimulating hormone, and most importantly, decreased 17-hydroxypregnenolone, supported a diagnosis of 17OHD. We sequenced the CYP17A1 gene of the patient and her parents, which demonstrated genetic defects (D487-S,488-F489 deletion and Y329K418X). 17OHD was diagnosed. The left adrenal tumor was assessed, and a non-functional adrenal incidentaloma was confirmed; NP-59 adrenal cortical scintigraphy and adrenal venous sampling showed no functional activity and non-lateralization. Hormone replacements with estrogen, spironolactone, and prednisolone were given. The patient became more feminized and confident, and her hypertension was controlled. Early diagnosis and treatment of 17OHD not only can prevent delay development of secondary sexual characteristics but also help the patient maintain mental health and improve their quality of life. In addition, the concomitant presence of a left adrenal tumor makes misdiagnosis of a functional adenoma more likely, possibly causing unnecessary surgery and delay inappropriate treatment.

scholarly journals MRKH syndrome: a review of literature

2018 ◽  
Vol 7 (12) ◽  
pp. 5219
Author(s):  
Nidhi Jain ◽  
Jyotsna Harlalka Kamra
Keyword(s):  
Ovarian Function ◽  
Surgical Techniques ◽  
Primary Amenorrhea ◽  
Mrkh Syndrome ◽  
Secondary Sexual Characteristics ◽  
Secondary Sexual Characters ◽  
Vaginal Aplasia ◽  
Rare Congenital Disorder ◽  
Sexual Characteristics ◽  
Secondary Sexual

Primary amenorrhea is defined as failure to achieve menarche till age of 14 years in absence of normal secondary sexual characters or till 16 years irrespective of secondary sexual characters. The most common cause of primary amenorrhea is gonadal pathology followed by Mayer-Rokitansky-Küster-Hauser syndrome (MRKH syndrome). MRKH syndrome is a rare congenital disorder characterised by uterine and vaginal aplasia. It occurs due to failure of development of Müllerian duct. Its incidence is 1 per 4500 female births. Mostly girls present with primary amenorrhea. It is characterised by presence of normal secondary sexual characteristics, normal 46 XX genotype, normal ovarian function in most of the cases and absent or underdeveloped uterus and upper part (2/3) of vagina. It is of two types: type A is isolated type while type B is associated with other renal/skeletal/cardiac anomalies. Treatment includes psychological counselling and vaginoplasty. Vaginoplasty can be done by various non-surgical and surgical techniques. The authors hereby review the literature of MRKH syndrome regarding its embryology, etiopathogenesis, approach to work up and management.

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