Publications

unusual distribution of zfy and zfx sequences on the sex chromosomes of the wood lemming, a species exhibiting xy sex reversal.	sex reversal occurs naturally in the wood lemming (myopus schisticolor) due to the presence in populations of this species of a variant (mutated) x chromosome, designated x. thus, xy animals develop into females, whereas xy animals develop into normal males. chromosome mapping by in situ hybridization of dna sequences homologous to the human zfy gene localized the wood lemming zfx sequences to region p12----p11 on both the wild-type x and the mutated x* chromosomes, at or proximal to a presume ...	1992	1349859
is the "mammalian" brown fat-specific mitochondrial uncoupling protein present in adipose tissues of birds?	1. mitochondria were isolated from the furcular, subcutaneous, abdominal, nape and lateral adipose tissue depots of five species of bird (pheasant, japanese quail, pigeon, house sparrow and great tit) acclimatized to the northern winter. 2. mitochondrial proteins were separated by sds-polyacrylamide gel electrophoresis, blotted onto nitrocellulose membranes, and probed for the presence of the 32,000-33,000 mr uncoupling protein characteristic of "mammalian" brown adipose tissue, using an anti-(g ...	1991	1756620
aberrant chromosomal sex-determining mechanisms in mammals, with special reference to species with xy females.	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/xy1y2 and x1x1x2x2/x1x2y. the original x or the y, respectively, have been translocated on to an autosome. the sex chromosomes of these species segregate regularly at meiosis; ...	1988	2907806
aberrant sex chromosome mechanisms in mammals. evolutionary aspects.	there are a number of mammalian species with complicated or unknown mechanisms for sex determination. the literature is reviewed with special reference to the origin and evolution of the sex chromosome mechanisms in three species of monotremes and in the following species of rodents: the creeping vole (microtus oregoni), the mole vole (ellobius lutescens), the amami spinous country rat (tokudaia osimensis), the wood lemming (myopus schisticolor), the varying lemming (dicrostonyx torquatus), sout ...	1983	6444170
sequence of centromere separation: role of centromeric heterochromatin.	the late metaphase-early anaphase cells from various tissues of male mus musculus, m. poschiavinus, m. spretus, m. castaneus, female and male bos taurus (cattle) and female myopus schisticolor (wood lemming) were analyzed for centromeres that showed separation into two daughter centromeres and those that did not show such separation. in all strains and species of mouse the y chromosome is the first one to separate, as is the x or y in the cattle. these sex chromosomes are devoid of constitutive ...	1982	6764903
x-linked genes of the h-y antigen system in the wood lemming (myopus schisticolor).	h-y antigen was investigated in 18 specimens representing six different sex chromosome constitutions of the wood lemming (myopus schisticolor). the control range of h-y antigen was defined by the sex difference between normal xx females (h-y negative per definitionem) and normal xy males (h-y positive, full titer). h-y antigen titers of the xy and x0 females were in the male control range, while in the x*x and x0 females the titers were intermediary. data were obtained with two different h-y a ...	1982	7042534
x-linked sex-reversing genes.	rearrangement of the x chromosome generates fertile xy females in the wood lemming, and a duplication has been discovered in xp21 in some xy females in the human. this has enabled identification and mapping of a novel sex-reversing gene in the human, double dosage of which blocks development of the testis. whether or not the human gene is related to the gene that causes sex reversal in the wood lemming remains to be seen. yet similar genes must exist in all eutherian mammals, according to ohno's ...	1998	9678362
xy sex reversal in the wood lemming is associated with deletion of xp21-23 as revealed by chromosome microdissection and fluorescence in situ hybridization.	in the wood lemming (myopus schisticolor), xy sex reversal occurs naturally because of the presence of an x chromosome variant designated x. the two types of x chromosome, x and x, can be distinguished by g-banding, and analyses have demonstrated complex rearrangements of the short arm of x*. here, chromosomal microdissection, degenerate oligonucleotide-primed polymerase chain reaction (dop-pcr) and fluorescence in situ hybridization (fish) techniques have been used to generate and map dna pro ...	1998	9872667
characterization of the xp21-23 region in the wood lemming, a region involved in xy sex reversal.	the wood lemming (myopus schisticolor) harbors two types of x chromosome, a normal x and a variant x, designated x. the x chromosome contains a mutation that causes xy sex reversal. we have previously demonstrated that the xp21-23 region is deleted from x* and is associated with xy sex reversal. to further analyze the deleted region, we have constructed and characterized seven x chromosome- and region-specific recombinant dna libraries. further, we have screened mouse fetal gonad cdna librarie ...	2001	11748603
a redescription of arostrilepis beringiensis (kontrimavichus et smirnova, 1991) and descriptions of two new species from palaearctic microtine rodents, arostrilepis intermedia sp. n. and a. janickii sp. n. (cestoda: hymenolepididae).	arostrilepis beringiensis (kontrimavichus et smirnova, 1991) is redescribed on the basis of its type specimens from lemmus trimucronatus (richardson) and material from the collections of the institute of systematics and ecology of animals, novosibirsk from the lemmings myopus schisticolor (lilljeborg) and lemmus sibiricus (kerr) from the asian part of russia. specimens previously identified as arostrilepis horrida (linstow, 1901) from voles are revised and newly collected materials are addressed ...	2011	22263310
meiotic behavior of gonosomically variant females of akodon azarae (rodentia, cricetidae).	the meiotic behavior of sex chromosomes has been investigated in variant females of akodon azarae, both in pachytene oocytes and metaphase i. in somatic cells, these females have a heteromorphic sex pair, in which the minor chromosome has been previously interpreted as a major deletion of the long arm of the x chromosome (dx). after microspreading for synaptonemal complex analysis, pachytene oocytes show two axes of very different lengths (100:17.1), which correspond to the sex chromosomes x and ...	1989	2692976
natural exceptions to normal gonad development in mammals.	gonads are the only organs with 2 possible developmental pathways, testis or ovary. a consequence of this unique feature is that mutations in genes controlling gonad development give rise not only to gonadal malformation or dysfunction but also to frequent cases of sex reversal, including xy females, xx males and intersexes. most of our current knowledge on mammalian sex determination, the genetic process by which the gonadal primordia are committed to differentiate as either testes or ovaries, ...	2013	22626995
[a new cestode species paranoplocephala gubanovi sp.n. (cyclophyllidea: anoplocephalidae) from the wood lemming myopus schisticolor of eastern siberia].	a new species of anoplocephalid cestode, paranoplocephala gubanovi sp. n. (cyclophyllidea, anoplocephalidae), from wood lemmings of eastern siberia (myopus schisticolor) is described. the new species differs from other known species of paranoplocephala associated with holarctic lemmings by having unique combination of characters as follows: a few-segmented strobila, superficial suckers sticking out of the scolex, ovary covering practically the whole middle part of the segment, relatively little ...	2007	14964849
comparative phylogeography and demographic history of the wood lemming (myopus schisticolor): implications for late quaternary history of the taiga species in eurasia.	the association between demographic history, genealogy and geographical distribution of mitochondrial dna cytochrome b haplotypes was studied in the wood lemming (myopus schisticolor), a species that is closely associated with the boreal forest of the eurasian taiga zone from scandinavia to the pacific coast. except for a major phylogeographic discontinuity (0.9% nucleotide divergence) in southeastern siberia, only shallow regional genetic structure was detected across northern eurasia. genetic ...	2008	18179438
long-term stability of allozyme frequencies in a wood lemming, myopus schisticolor, population with a biased sex ratio and density fluctuations.	wood lemming (myopus schisticolor) populations are characterized by female biased sex ratios and cyclic variations in population size. both of these characteristics are assumed to reduce genetic variation and thus affect the evolutionary adaptation of the species. we addressed these questions by studying the genetic structure of a wood lemming population from eastern finland by isozyme markers during a 21-year period, which corresponds to 40-50 generations. contingency tests showed that genotypi ...	2005	15674383
em studies of female meiosis in wood lemmings with different sex chromosome constitutions.	the chromosomes were studied throughout meiotic prophase by electron microscopy of surface-spread oocytes from one xx, four xx, and three xy female wood lemmings, myopus schisticolor. the x* chromosome had originated from x by a deletion and an inversion in the short arm. the deletion was confirmed in pachytene cells from x*x females; a d-loop was present in the sex bivalent in 16.8% of the cells, and asynapsis of unequal ends was seen in 9.1% of other cells. at late pachytene the d-loop under ...	2001	11555858
gonadal development and birth weight in xx and xy females of the wood lemming, myopus schisticolor.	a quantitative histological analysis of ovaries from 8- to 10-day-old wood lemmings revealed significant differences between females with xy and xx sex chromosome constitutions. the ovarian volume of xy females was on average 57% of xx, and the number of oocytes was less than half in xy compared to xx. however, the frequency of growing oocytes in relation to the total number was 6.5% for xy compared to 3.0% for xx. oogenesis in x*y wood lemmings resembles in many respects that of mice he ...	2000	11173838
telomeric (ttaggg)n sequences are associated with nucleolus organizer regions (nors) in the wood lemming.	the distribution of the (ttaggg)n telomeric sequence was studied in chromosomes of the wood lemming, myopus schisticolor, by fluorescence in-situ hybridization. as expected, the hybridization signals were observed at telomeres of all chromosomes. however, quite a number of interstitial telomeric sites were present in the pericentric heterochromatic regions. consistent strong hybridization signals were also seen at one terminus of chromosomes 5, 7 and 12--15. by post-hybridization g-banding and s ...	1999	10421383
genetic conflicts and the paradox of sex determination: three paths to the evolution of female intersexuality in a mammal.	that sex determining systems ever change is paradoxical but can be explained by noting that conflict between selfish elements and their modifiers will often cause a shift in sex determining strategy. the evolution of the novel sex determining system of moles (talpa europaea and t. occidentalis) may, we argue, be an example of just such a process. three different models for the evolution of female intersexuality are presented. these all attempt to account for (1) the fact that a few years ago pop ...	1996	8762333
genetic differentiation among populations of myopus schisticolor (the wood lemming)--isozyme variation.	to investigate genetic differentiation among populations of the wood lemming myopus schisticolor (muridae, rodentia) isozyme variation in 10 populations from three regions, fennoscandia, western and eastern siberia, was examined. from 20 loci examined, the two most polymorphic ones, idh-1 and pgi-1, were used in the complete survey. the results of hierarchical f-statistics analysis showed significant differentiation among all populations; single locus fpt values agreed well (idh-1, fpt = 0.20; p ...	1995	7706113
metabolism, thermogenesis and daily rhythm of body temperature in the wood lemming, myopus schisticolor.	wood lemmings (myopus schisticolor) were captured during their autumnal migration in september and october. the animals were maintained at 12 degrees c and under 12l:12d photoperiod. basal metabolic rate and thermogenic capacity of the wood lemming were studied. basal metabolic rate was 3.54 ml o2.g-1.h-1, which is 215-238% of the expected value. the high basal metabolic rate seems to be typical of rodents living in high latitudes. the body temperature of the wood lemming was high (38.0-38.8 deg ...	1993	8151013
relationship between nucleoli and sex chromosomes during meiosis of the male wood lemming myopus schisticolor: a fine-structure study.	electron microscopy of ultrathin serial sections has been used to study the origin and fate of a mass of fibrillar material (fm) during spermatogenesis in the wood lemming myopus schisticolor. in the course of early pachytene, one of the two nucleoli completely disappears. the remaining nucleolus loses its granular portion and acquires a "round body" encased by the fibrillar moiety, and the restructuring is accompanied by the appearance of fm in the close vicinity of this nucleolus. during diaki ...	1987	2960401
the h-y transplantation antigen is present in xo and x*x female wood lemmings (myopus schisticolor).		1985	3905586
correlation between sexual phenotype and x-chromosome inactivation pattern in the x*xy wood lemming.	replication patterns of the x chromosomes were studied in xxy wood lemmings with male and female phenotypes. the wild-type x was late replicating (ie, inactivated) in all cells of the xxy female, whereas the mutated x* was late replicating in all cells of the x*xy male. these findings are compared with those obtained in sex-reversed (sxr) mice.	1985	3884284
female wood lemmings with the mutant x*-chromosome carry the h-y transplantation antigen.		1985	3881341
evidence for x-linkage and non-inactivation of steroid sulphatase locus in wood lemming.		1982	7040982
sex determination and phenotype in wood lemmings with xxy and related karyotypic anomalies.		1981	7026418
on the evolutionary stability of the female-biased sex ratio in the wood lemming (myopus schisticolor): the effect of inbreeding.	the evolutionary stability of the female-biased sex ratio observed in the wood lemming (myopus schisticolor) is discussed. the hypothesis analysed is that the skewed sex ratio is maintained as a result of partial and/or recurrent inbreeding. fredga et al. (1976, 1977) have suggested that an x-linked mutant gene, x, affects the male-determining action of the y chromosome, thus converting some xy individuals into females. by a mechanism of selective non-disjunction in the foetal ovary only x-carry ...	1978	282283
testicular cells lysostripped of h-y antigen organize ovarian follicle-like aggregates.	a suspension of free testicular cells were obtained by mild trypsin treatment from newborn balb/c testes, and their plasma membrane h-y antigen sites were blocked (lysostripped) by an excess of h-y antibody of proven specificity and potency (45 min in ice). upon 16 h of the moscona-type rotation culture, these treated testicular cells yielded primarily spherical aggregates, more than half of which demonstrated a strong resemblance to ovarian follicles. the resemblance was particularly striking b ...	1978	77209
h-y antigen and the origin of xy female wood lemmings (myopus schisticolor).		1976	1004604
fertile xx- and xy-type females in the wood lemming myopus schisticolor.		1976	1272393
sex-chromosome aberrations in wood lemmings (myopus schisticolor).	the wood lemming displays certain peculiar features: (1) the sex ratio shows a prevalence of females (frank, 1966; kalela and oksala, 1966), and some females produce only female offspring (kalela and oksala, 1966). (2) in a considerable proportion (in the present material, slightly less than half) of the females, an xy chromosome complement is found in the somatic tissues, but the y is absent in the germ line of those studied (fredga et al., 1976). therefore, (3) a mechanism of double nondisjunc ...	1976	17494626