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P M Borodin

Publications and source records attributed to P M Borodin.

At least 19 recordsLinked to original sources
PubMed2006

Inheritance of litter size at birth in farmed arctic foxes (Alopex lagopus, Canidae, Carnivora).

Natural populations of the arctic fox (Alopex lagopus, Canidae, Carnivora) differ drastically in their reproductive strategy. Coastal foxes, which depend on stable food resources, produce litters of moderate size. Inland foxes feed on small rodents, whose populations are characterized by cycling fluctuation. In the years with low food supply, inland fox populations have a very low rate of reproduction. In the years with high food supply, they undergo a population explosion. To gain insight into the genetic basis of the reproductive strategy of this species, we performed complex segregation analysis of the litter size in the extended pedigree of the farmed arctic foxes involving 20,665 interrelated animals. Complex segregation analysis was performed using a mixed model assuming that the trait was under control of a major gene and a large number of additive genetic and random factors. To check the significance of any major gene effect, we used Elston-Stewart transmission probability test. Our analysis demonstrated that the inheritance of this trait can be described within the frameworks of a major gene model with recessive control of low litter size. This model was also supported by the pattern of its familial segregation and by comparison of the distributions observed in the population and that expected under our model. We suggest that a system of balanced polymorphism for litter size in the farmed population might have been established in natural populations of arctic foxes as a result of adaptation to the drastic fluctuations in prey availability.

Animals↗
PubMed2006

Identification of all pachytene bivalents in the common shrew using DAPI-staining of synaptonemal complex spreads.

A major problem in studies of synaptonemal complexes (SC) is the difficulty in distinguishing individual chromosomes. This problem can be solved combining SC immunostaining with FISH of chromosome-specific sequences. However, this procedure is expensive, time-consuming and applicable only to a very limited number of species. In this paper we show how a combination of SC immunostaining and DAPI staining can allow identification of all chromosome arms in surface-spreads of the SC of the common shrew (Sorex araneus L.). Enhancement of brightness and contrast of the images with photo editing software allowed us to reveal clear DAPI-positive and negative bands with relative sizes and positions similar to DAPI landmarks on mitotic metaphase chromosomes. Using FISH with DNA probes prepared from chromosome arms m and n we demonstrated correct recognition of the chromosomes mp and hn on the basis of their DAPI pattern. We show that the approach we describe here may be applied to other species and can provide an important tool for identification of individual bivalents in pachytene surface-spreads.

Animals↗
PubMed2006

Reproductive isolation due to the genetic incompatibilities between Thrichomys pachyurus and two subspecies of Thrichomys apereoides (Rodentia, Echimyidae).

We tested intrinsic reproductive isolation between 3 taxa of the South American caviomorph rodent Thrichomys (Rodentia, Echimyidae): T. pachyurus, T. apereoides subsp. apereoides and T. apereoides subsp. laurentius. They were mated in captivity and produced viable progeny. Some F1 hybrid females were fertile, whereas all F1 males were sterile. Histological examination revealed meiotic arrest at the primary spermatocyte stage. No sperm was detected in testes or epididymes. Electron microscopic analysis of surface spread synaptonemal complexes revealed a complete failure of chromosome pairing in F1 hybrids of T. pachyurus with T. apereoides subsp. laurentius and T. apereoides subsp. apereoides. In the male hybrids between T. apereoides subsp. apereoides and T. apereoides subsp. laurentius, meiosis did not proceed beyond diplotene, although all of the chromosomes, including heteromorphic ones, paired in an orderly fashion. Backcross males with homomorphic karyotypes showed segregation in meiosis progression. This indicates that male hybrid sterility is due to genetic, but not chromosomal, incompatibility of the parental taxa.

Animals↗
PubMed2006

[Polymorphism of dental formula and segregation of its variants in a pedigree of kerry blue terrier dogs].

Polymorphism of the dental formula was analyzed in a sophisticated pedigree of Kerry Blue Terrier. A lack of one or more lower premolars was observed in some dogs. Two different patterns of missing teeth were identified. One pattern consisted in agenesis of a second premolar, often in combination with agenesis of neighbor teeth, including the fourth premolar. In the second pattern, agenesis of a fourth premolar was expressed as an isolated abnormality. It was shown previously that the first pattern is inherited as a recessive trait with near complete penetrance. In this work, the control of a major-gene was demonstrated for the second pattern. This abnormality develops in 70-80% of mutant homozygotes and in no more than 20% of heterozygotes and wild-type homozygotes. It was shown that the two dentition abnormalities are controlled by different genes, which were designated LPA2 and LPA4 (Lower Premolar Agenesis).

Animals↗
PubMed2006

[Changes in litter size in Kerry blue terrier dogs with abnormal dentition].

The pleiotropic effects of mutations resulting in abnormal dentition were analyzed in Kerry Blue Terrier. A decrease in litter size was demonstrated for dogs with dentition anomalies. The mean litter size was 5.72 puppies when both parents had normal dentition and 3.64 puppies when the parents had hypodontia. Analysis showed that the decrease in litter size cannot be fully explained by the effect of inbreeding and is most probably associated with the pleiotropic effect of the genes controlling teeth development on the embryonic viability.

Animals↗
PubMed2005

[Genetic control of chromosome synapsis in mice heterozygous for a paracentric inversion].

Frequencies of formation of inversion loops and their relative sizes were studied in laboratory mice heterozygous at paracentric inversion In1(1)Rk in chromosome 1, depending on the genetic background. Homozygotes In1/In1 were crossed with mice from five inbred strains (A/HeJ, BALB/cJ, C3H/HeJ, C57BL/6J, DBA2/J). The frequency of formation of inversion loops, their relative sizes, and the dependence of these parameters on the stage of pachitene were analyzed on electron-microscopic slides of spread spermatocytes in first-generation hybrids. It was shown that the genetic background and cross direction statistically significantly influenced the duration of individual pachitene stages and the frequency of inversion loops, but not relative loop size. Using a database on SNP distribution in the inbred strains examined, we carried out in silico mapping of genes affecting the genotype-dependent characters. We have found that the efficiency of synapsis in the inversion does not depend on interstrain differences in homology of the chromosome 1 region involved in the inversion. Genes controlling the inversion loop frequency in the inversion heterozygotes were mapped to chromosome 7, and genes controlling the duration of individual pachitene stages, to chromosomes 2 and 5.

Animals↗
PubMed2002

Inheritance of litter size at birth in the Brazilian grass mouse (Akodon cursor, Sigmodontinae, Rodentia).

By means of complex segregation analysis we studied the inheritance of litter size in two large pedigrees of captive-bred colonies of the Brazilian grass mouse Akodon cursor. Genetic analysis has revealed a highly significant influence of genetic factors on the variation of litter size (heritability, h2, was estimated as 0.44). The inheritance followed the classical polygene model: neither the major-gene model nor the polygene with unequal contribution model described the data significantly better.

Animals↗
PubMed2002

B chromosomes of Korean field mouse Apodemus peninsulae (Rodentia, Murinae) analysed by microdissection and FISH.

Organization of B chromosomes in the Korean field mouse Apodemus peninsulae was analyzed. We painted its metaphase chromosomes with whole and partial chromosome paints generated by microdissection and DOP-PCR. The results of the painting indicated that all B chromosomes contained a large amount of repeated DNA sequences. The repeats could be classified in terms of their homology and predominant location. Pericentromeric repeats of B chromosomes were present in many copies in pericentromeric C-blocks of all autosomes and in non-centromeric C-blocks of the sex chromosomes. B arm specific type 1 repeats comprised the main body of the arms of almost all B chromosomes and were present in the arms of A chromosomes as interspersed sequences. B arm-specific type 2 repeats were found at the ends of some B chromosomes that did not undergo compaction at the interphase- metaphase transition and remained uncondensed. On the basis of comparative analysis of localization of B chromosome repeats in the chromosomes of two related species, A. peninsulae and A. agrarius, we suggest a hypothesis of B chromosome origin and evolution in the genus Apodemus.

Animals↗
PubMed2001

Segregation analysis of Scheuermann disease in ninety families from Siberia.

Scheuermann disease [OMIM number 181440] is the most common cause of structural kyphosis in adolescence. Segregation analysis using a model with gender effects was applied to 90 pedigrees from Barnaul (West Siberia, Russia) ascertained through a proband with Scheuermann disease. The transmission probability model was used to detect major gene effect. A significant contribution of a major gene to the control of the pathology was established. Inheritance of the disease can be described within the framework of a dominant major gene diallele model. According to this model, Scheuermann disease should never occur in the absence of the mutant allele. All male carriers of the mutant allele develop the disease, while only a half of female carriers manifest it. We found a high frequency of idiopathic scoliosis in the families with Scheuermann disease (0.08 vs. 0.01-0.02 in general population). We also observed a succession of idiopathic scoliosis and Scheuermann disease in consecutive generations. The familial aggregation of these two spinal pathologies in the present sample may indicate a genetic unity of Scheuermann disease and idiopathic scoliosis.

Adolescent↗
PubMed2001

Pericentric inversion in natural populations of Oligoryzomys nigripes (Rodentia: Sigmodontinae).

We analysed polymorphism for pericentric inversion in chromosome 3 of Oligoryzomys nigripes (Rodentia: Sigmodontinae) in several populations in Brazil and examined the meiotic behaviour of this chromosome in heterozygotes. We observed an orderly pairing of all chromosomes at pachytene in heterozygotes for the inverted chromosome 3. No indication of meiotic arrest and germ-cell death was found. Electron microscopy of synaptonemal complexes and conventional meiotic analysis indicated strictly nonhomologous synapsis and crossing-over suppression in the inverted region in the heterozygotes, which prevent the formation of unbalanced gametes. Thus, the pericentric inversion in chromosome 3 does not apparently result in any selective disadvantages in heterozygous carriers. In the majority of the populations studied, the frequencies of acrocentric homozygotes, metacentric homozygotes, and heterozygotes were in Hardy-Weinberg equilibrium. However, in some populations, we detected an excess of heterozygotes and a deficiency of acrocentric homozygotes.

Animals↗
PubMed2001

Pattern of X-Y chromosome pairing in the Taiwan vole, Microtus kikuchii.

Pairing of X and Y chromosomes at meiotic prophase and the G- and C-banding patterns and nucleolar organizer region (NOR) distribution were analyzed in Microtus kikuchii. M. kikuchii is closely related to M. oeconomus and M. montebelli, karyologically and systematically. The formation of a synaptonemal complex between the X and Y chromosomes at pachytene and end-to-end association at diakinesis--metaphase I are only observed in three species in the genus Microtus; M. kikuchii, M. oeconomus, and M. montebelli. All the other species that have been studied so far have had asynaptic X-Y chromosomes. These data confirm that M. kikuchii, M. oeconomus, and M. montebelli are very closely related, and support the separation of asynaptic and synaptic groups on the phylogenetic tree.

Animals↗
PubMed2001

[Chromosomal evolution of the Common Shrew Sorex araneus L.from the Southern Ural and Siberia in the postglacial period].

This paper summarizes a series of studies on chromosomal geography of the common shrew Sorex araneus L. in Siberia and the Southern Urals. Chromosomal races inhabiting the Southern Urals and the Western Siberian Plain sequentially replace each other in the latitudinal direction. In this region, karyotypes of each two adjacent races differ from each other by a single whole-arm reciprocal translocation. In the Eastern Siberian branch, the neighboring races differ mainly in the number or set of metacentric chromosomes. Analysis of the race distribution in the common shrew in the context of paleophysiology of the glacial period allowed us to reconstruct the sequence of events leading to the establishment of the present-day structure of the species.

Animals↗
PubMed2000

Comparative cytogenetics of hamsters of the genus Calomyscus.

Karyotypes of Calomyscus from different regions of Turkmenistan, Iran, and Azerbaijan were studied using chromosome banding (G- and C-banding) and analyses of meiosis in laboratory hybrids. Extensive variation in the diploid number and the number of autosomal arms (FNa) was revealed (2n = 30, FNa = 44; 2n = 32, FNa = 42; 2n = 44, FNa = 46; 2n = 44, FNa = 58; 2n = 37, FNa = 44; 2n = 50, FNa = 50; 2n = 52, FNa = 56). Centric and tandem fusions and heterochromatin changes were identified as the major modes of karyotype evolution in this group. Natural hybrids between individuals with different karyotypes were recorded, and regular chromosome pairing in meiosis was observed in laboratory hybrids. Fluorescence in situ hybridization with a 353-bp BspRI complex tandem repeat indicated that chromosomal repatterning occurred recently within the genus. There is no unequivocal evidence suggesting the role of chromosomal change in the speciation of the populations of Calomyscus examined.

Animals↗
PubMed2000

Robertsonian metacentrics of the house musk shrew (Suncus murinus, Insectivora, Soricidae) lose the telomeric sequences in the centromeric area.

The house musk shrew, Suncus murinus, is polymorphic for five Robertsonian translocations (Rb8.17, 9.13, 10.12, 11.16, 14.15). Fluorescence in situ hybridisation with a biotin-labelled oligonucleotide, (TTAGGG)7, was performed to localise the telomeric DNA sequences at Rb chromosomes of heterozygous shrews. Hybridisation signals were observed at both ends of all chromosomes, but not at the pericentromeric areas of any of the Robertsonian metacentrics. Our results indicate a complete loss of the telomeric sequences at the fusion points of the Rb metacentrics in S. murinus.

Animals↗
PubMed2000

Genetic modification of mammalian genome at chromosome level.

The review is concerned with a progress in genetic modification of a mammalian genome in vitro and in vivo at chromosomal level. Recently three new approaches for the chromosome biotechnology have been developed: Using Cre/loxP-system a researcher is able to produce targeted rearrangements of whole chromosomes or their segments or particular genes within the genome, and therefore to modify the set, position and copy number of the endogenous elements of the genome. Mammalian artificial chromosomes (MACs) provide a possibility to introduce into genome relatively large segments of alien chromosome material, either artificially constructed or derived from the genome of different species. Using ES-somatic cell hybrids allows to transfer whole chromosomes or their fragments between different genomes within and between species. Advantages and limitations of these approaches are discussed.

Animals↗
PubMed1999

Segregation analysis of idiopathic scoliosis: demonstration of a major gene effect.

Segregation analysis using a model with age and gender effects was applied to 101 pedigrees ascertained through a proband with idiopathic scoliosis. The transmission probability model was used to detect major gene effect. When we analyzed the pedigrees where affected status was assigned to persons with a Cobb's angle of more than 5 degrees we did not detect a significant major gene effect. However, when the affected status was assigned to persons with pronounced forms of disease only (a curve of at least 11 degrees) a significant contribution of a major causal gene could be established and inheritance could be described according to a dominant major gene diallele model, assuming incomplete sex and age dependent penetrance of genotypes. According to this model, the pronounced forms of idiopathic scoliosis should never occur in the absence of the mutant allele. This indicates that only the carriers of the mutant allele develop pronounced forms of the disease. At the same time, only a fraction of the carriers of the mutant gene should manifest the disease (30% of males and 50% of females).

Adolescent↗
PubMed1999

[Chromosomal localization of 10 genes on the cytogenetic map of the common shrew Sorex araneus L].

Using a panel of hybrid clones (common shrew--Chinese hamster and common shrew--mouse), the syntheny and localization of the following genes was determined: genes for alpha-galactosidase (GLA), acid phosphatase (ACP1), and phosphoglycerate kinase (PGK1) on chromosome de; adenosine kinase (ADK) and glucuronidase 2 (GUS2) on chromosome ik; glutamic-oxaloacetic transaminase 2 (GOT2) and peptidase D (PEPD) on chromosome hn; and glyoxalase 1 (GLO1) and phosphoglucomutase 2 (PGM2) on chromosome go. Gene for beta-galactosidase (GLB1) was assigned to arm p of chromosome mp. Thus, including previously mapped genes, the cytogenetic map of the common shrew contains 39 genes. They form seven syntheny groups and mark eight out of ten chromosomes.

Animals↗