Gonadal development and birth weight in X*X and X*Y females of the wood lemming, Myopus schisticolor

2000 ◽  
Vol 91 (1-4) ◽  
pp. 97-101 ◽  
Author(s):  
K. Fredga ◽  
L. Setterfield ◽  
U. Mittwoch
Keyword(s):  
Birth Weight ◽  
Gonadal Development ◽  
Wood Lemming ◽  
Myopus Schisticolor

scholarly journals 408 Cases of Genital Ambiguity Followed by Single Multidisciplinary Team during 23 Years: Etiologic Diagnosis and Sex of Rearing

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Georgette Beatriz De Paula ◽  
Beatriz Amstalden Barros ◽  
Stela Carpini ◽  
Bruna Jordan Tincani ◽  
Tais Nitsch Mazzola ◽  
...  
Keyword(s):  
Birth Weight ◽  
Low Birth Weight ◽  
Gonadal Dysgenesis ◽  
Disorders Of Sex Development ◽  
Ambiguous Genitalia ◽  
Gonadal Development ◽  
Hydroxylase Deficiency ◽  
Salt Wasting ◽  
Genital Ambiguity ◽  
21 Hydroxylase Deficiency

Objective. To evaluate diagnosis, age of referral, karyotype, and sex of rearing of cases with disorders of sex development (DSD) with ambiguous genitalia.Methods. Retrospective study during 23 years at outpatient clinic of a referral center.Results. There were 408 cases; 250 (61.3%) were 46,XY and 124 (30.4%) 46,XX and 34 (8.3%) had sex chromosomes abnormalities. 189 (46.3%) had 46,XY testicular DSD, 105 (25.7%) 46,XX ovarian DSD, 95 (23.3%) disorders of gonadal development (DGD), and 19 (4.7%) complex malformations. The main etiology of 46,XX ovarian DSD was salt-wasting 21-hydroxylase deficiency. In 46,XX and 46,XY groups, other malformations were observed. In the DGD group, 46,XY partial gonadal dysgenesis, mixed gonadal dysgenesis, and ovotesticular DSD were more frequent. Low birth weight was observed in 42 cases of idiopathic 46,XY testicular DSD. The average age at diagnosis was 31.7 months. The final sex of rearing was male in 238 cases and female in 170. Only 6.6% (27 cases) needed sex reassignment.Conclusions. In this large DSD sample with ambiguous genitalia, the 46,XY karyotype was the most frequent; in turn, congenital adrenal hyperplasia was the most frequent etiology. Malformations associated with DSD were common in all groups and low birth weight was associated with idiopathic 46,XY testicular DSD.

scholarly journals A hypothesis explaining the exceptional sex ratio in the wood lemming (Myopus schisticolor)

Hereditas ◽  
2009 ◽  
Vol 85 (1) ◽  
pp. 101-104 ◽  
Author(s):  
KARL FREDGA ◽  
ALFRED GROPP ◽  
HEINZ WINKING ◽  
FRITZ FRANK
Keyword(s):  
Sex Ratio ◽  
Wood Lemming ◽  
Myopus Schisticolor

Aberrant chromosomal sex-determining mechanisms in mammals, with special reference to species with XY females

1988 ◽  
Vol 322 (1208) ◽  
pp. 83-95 ◽  
Keyword(s):  
Sex Determination ◽  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Mammalian Species ◽  
Y Chromosomes ◽  
Wood Lemming ◽  
Xx Males ◽  
Original Size ◽  
Myopus Schisticolor ◽  
Dicrostonyx Torquatus

Both mouse and man have the common XX/XY sex chromosome mechanism. The X chromosome is of original size (5-6% of female haploid set) and the Y is one of the smallest chromosomes of the complement. But there are species, belonging to a variety of orders, with composite sex chromosomes and multiple sex chromosome systems: XX/XY 1 Y 2 and X 1 X 1 X 2 X 2 /X 1 X 2 Y. The original X or the Y, respectively, have been translocated on to an autosome. The sex chromosomes of these species segregate regularly at meiosis; two kinds of sperm and one kind of egg are produced and the sex ratio is the normal 1:1. Individuals with deviating sex chromosome constitutions (XXY, XYY, XO or XXX) have been found in at least 16 mammalian species other than man. The phenotypic manifestations of these deviating constitutions are briefly discussed. In the dog, pig, goat and mouse exceptional XX males and in the horse XY females attract attention. Certain rodents have complicated mechanisms for sex determination: Ellobius lutescens and Tokudaia osimensis have XO males and females. Both sexes of Microtus oregoni are gonosomic mosaics (male OY/XY, female XX/XO). The wood lemming, Myopus schisticolor , the collared lemming, Dicrostonyx torquatus , and perhaps also one or two species of the genus Akodon have XX and XY females and XY males. The XX, X*X and X*Y females of Myopus and Dicrostonyx are discussed in some detail. The wood lemming has proved to be a favourable natural model for studies in sex determination, because a large variety of sex chromosome aneuploids are born relatively frequently. The dosage model for sex determination is not supported by the wood lemming data. For male development, genes on both the X and the Y chromosomes are necessary.

Home range size and activity of the wood lemming, Myopus schisticolor

Ecography ◽  
1991 ◽  
Vol 14 (2) ◽  
pp. 138-141 ◽  
Author(s):  
Harry P. Andreassen ◽  
Soren Bondrup-Nielsen
Keyword(s):  
Home Range ◽  
Home Range Size ◽  
Range Size ◽  
Wood Lemming ◽  
Myopus Schisticolor
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