Studies on sex differentiation and sex determination in amphibians. IV. The geographical distribution of the sex races of the European grass frog (Rana temporaria, L.). A contribution to the problem of the evolution of sex

1930 ◽  
Vol 56 (2) ◽  
pp. 149-165 ◽  
Author(s):  
Emil Witschi
Keyword(s):  
Sex Determination ◽  
Geographical Distribution ◽  
Rana Temporaria ◽  
Sex Differentiation ◽  
Evolution Of Sex ◽  
Frog Rana Temporaria

scholarly journals Within-population polymorphism of sex-determination systems in the common frog (Rana temporaria )

2013 ◽  
Vol 26 (7) ◽  
pp. 1569-1577 ◽  
Author(s):  
N. Rodrigues ◽  
C. Betto-Colliard ◽  
H. Jourdan-Pineau ◽  
N. Perrin
Keyword(s):  
Sex Determination ◽  
Rana Temporaria ◽  
Common Frog ◽  
Population Polymorphism ◽  
Frog Rana Temporaria ◽  
The Common

scholarly journals Molecular evolution of Dmrt1 accompanies change of sex-determining mechanisms in reptilia

2014 ◽  
Vol 10 (12) ◽  
pp. 20140809 ◽  
Author(s):  
Daniel E. Janes ◽  
Christopher L. Organ ◽  
Rami Stiglec ◽  
Denis O'Meally ◽  
Stephen D. Sarre ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Molecular Evolution ◽  
Sex Determination ◽  
Sex Differentiation ◽  
Evolution Of Sex ◽  
Temperature Dependent ◽  
Exon 2 ◽  
Ancestral Condition ◽  
Genotypic Sex Determination

In reptiles, sex-determining mechanisms have evolved repeatedly and reversibly between genotypic and temperature-dependent sex determination. The gene Dmrt1 directs male determination in chicken (and presumably other birds), and regulates sex differentiation in animals as distantly related as fruit flies, nematodes and humans. Here, we show a consistent molecular difference in Dmrt1 between reptiles with genotypic and temperature-dependent sex determination. Among 34 non-avian reptiles, a convergently evolved pair of amino acids encoded by sequence within exon 2 near the DM-binding domain of Dmrt1 distinguishes species with either type of sex determination. We suggest that this amino acid shift accompanied the evolution of genotypic sex determination from an ancestral condition of temperature-dependent sex determination at least three times among reptiles, as evident in turtles, birds and squamates. This novel hypothesis describes the evolution of sex-determining mechanisms as turnover events accompanied by one or two small mutations.

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.

The First Record of Tesselated Snake, Natrix tesselata Laurenti, 1768 in the Central Chernozem Territory of Russia and Some Other Results of the Herpetological Research in the Upper Don

2011 ◽  
Vol 4 (2) ◽  
pp. 192-194
Author(s):  
Georgy A. Lada ◽  
V. Y. Nedosekin
Keyword(s):  
Rana Temporaria ◽  
First Record ◽  
Isolated Population ◽  
Common Frog ◽  
Northern Border ◽  
Frog Rana Temporaria ◽  
Bombina Bombina ◽  
Central Chernozem

A small isolated population of tesselated snake, Natrix tesselata was found in the Upper Don (Lipetsk Region, Russia). It is the first record of this species in the Central Chernozem Territory of Russia, which is separated from the northern border of the main range by the distance of about 200 km. An isolated population of common frog, Rana temporaria and phenetically peculiar population of fire-bellied toad, Bombina bombina are found here too. Faunistic aspect of new herpetological records is discussed.

scholarly journals Evolution of Sex Determination in Caenorhabditis: Unusually High Divergence of tra-1 and Its Functional Consequences

Genetics ◽  
1996 ◽  
Vol 144 (2) ◽  
pp. 587-595 ◽  
Author(s):  
Mario de Bono ◽  
Jonathan Hodgkin
Keyword(s):  
Sex Determination ◽  
Germ Line ◽  
Amino Acid Identity ◽  
Evolution Of Sex ◽  
Phenotypic Differences ◽  
C Elegans ◽  
Functional Studies ◽  
Somatic Gonad ◽  
Functional Consequences ◽  
Significant Divergence

Abstract The tra-1 gene is a terminal regulator of somatic sex in Caenorhabditis elegans: high tra-1 activity elicits female development, low tra-1 activity elicits male development. To investigate the function and evolution of tra-1, we examined the tra-1 gene from the closely related nematode C. briggsae. Ce-tra-1 and Cb-tra-1 are unusually divergent. Each gene generates two transcripts, but only one of these is present in both species. This common transcript encodes TRA-1A, which shows only 44% amino acid identity between the species, a figure much lower than that for previously compared genes. A Cb-tra-1 transgene rescues many tissues of tra-1(nul1) mutants of C. elegans but not the somatic gonad or germ line. This transgene also causes nongonadal feminization of XO animals, indicating incorrect sexual regulation. Alignment of Ce-TRA-1A and Cb-TRA-1A defines several conserved regions likely to be important for tra-1 function. The phenotypic differences between Ce-tra-1(null) mutants rescued by Cb-tra-1 transgenes and wild-type C. elegans indicate significant divergence of regulatory regions. These molecular and functional studies suggest that evolution of sex determination in nematodes is rapid and genetically complex.

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