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At least 19 recordsLinked to original sources
PubMed1991

The effect of H-2 region and genetic background on hormone-induced ovulation rate, puberty, and follicular number in mice.

We have examined the effects of major histocompatibility (H-2) haplotypes and genetic background (all loci other than the H-2 region) on hormone-induced ovulation rate in congenic strains of mice. In comparison with the H-2a haplotype, the H-2b haplotype increased hormone-induced ovulation rate 92% on the A/J (A) genetic background. However, H-2 haplotype did not affect hormone-induced ovulation rate on the C57BL/10J (C57) genetic background. The H-2b-linked gene(s) increased hormone-induced ovulation rate on the A/J genetic background largely by (1) enhancing the maturation of follicles in response to pregnant mare's serum gonadotrophin (PMSG) and (2) altering the stages of follicular development which can be induced to ovulate in response to human chorionic gonadotrophin (hCG). The observed effects of H-2 on hormone-induced ovulation rate were not explained by differences in the timing of puberty, the number of follicles present in untreated females, or the incidence of follicular atresia. The effect of genetic background on hormone-induced ovulation rate was much greater than was the effect of the H-2 region. We found that hormone-induced ovulation rate was five- to six-fold higher on the C57 genetic background than on the A genetic background. The C57 genetic background increased hormone-induced ovulation rate by (1) enhancing the induction of follicular maturation in response to gonadotropins and (2) by reducing the incidence of follicular atresia.

Animals↗
PubMed1992

Craniometric measurements of craniofacial malformations in the X-linked hypophosphatemic (Hyp) mouse on two different genetic backgrounds: C57BL/6J and B6C3H.

This study reports data on craniometric measurements in the X-linked hypophosphatemic (Hyp) mouse on two different genetic backgrounds: C57BL/6J and B6C3H. Heads of normal females "+/+," normal males "+/Y," heterozygous mutant females "Hyp/+," and hemizygous mutant males "Hyp/Y" for each genetic background were examined. Data were collected via skull measurements. On a C57BL/6J background, the neurocranium of mutants "Hyp/+" and "Hyp/Y" was shorter and slightly higher than in normal counterparts. On a B6C3H background, mutant mice "Hyp/+" and "Hyp/Y" were shorter in neurocranial length than in normal counterparts. Viscerocranial height was larger in "Hyp/Y" than in normal counterparts. No differences in neurocranial and mandibular height were found. Mutant mice on a C57BL/6J background were compared to mutant mice on a B6C3H background. No differences in neurocranial length were found. Cranial length was shorter in "Hyp/Y" on C57BL/6J than in "Hyp/+" on B6C3H. Facial length parameters were shorter in "Hyp/Y" on C57BL/6J than in "Hyp/Y" and "Hyp/+" mutant mice on B6C3H. Mandibular length was shorter in "Hyp/Y" on C57BL/6J than in "Hyp/+" on C57BL/6J and both mutant mice ("Hyp/Y" and "Hyp/+") on a B6C3H background. The results of this study indicate that craniofacial growth is less affected in mutant mice on a B6C3H genetic background than in mutant mice on a C57BL/6J genetic background.

Animals↗
PubMed1975

Effect of the genetic background on recombination frequency in the cn-vg region of the second chromosome of natural populations of Drosophila melanogaster.

Newly established test stocks made it possible to follow the effect of three different defined genetic backgrounds (first and third chromosomes) on recombination frequency in the cn-vg region of the second chromosomes isolated from four natural populations of Drosophila melanogaster. One background was composed of the chromosomes with inversions obtained from the stock (see article) and another two backgrounds were of the standard type consisting one-half of the original chromosomes from the natural population and one-half of the chromosomes of the stocks Oregon R or Samarkand. Using the analysis of variance significant differences in RF values were found between and within populations and especially between the different backgrounds. Some simple and double interactions between the above factors played a role. The highest RF values were obtained on the background [corrected] with inversions. The effect of the different genetic backgrounds [corrected] by the action of the genetic modifiers of RF. The different genetic backgrounds affected the variations in RF values in individual populations and the different populations reacted differentially to the changed genetic background. The design of the experiment permitted an estimation of the causal compoenents of variance and heritability of RF from the sib analysis. The additive component of variance was present in only two of the populations under test; the respective estimates of heritability were very low.

Animals↗
PubMed1986

Lung defenses against Pseudomonas aeruginosa in C5-deficient mice with different genetic backgrounds.

Lung defenses against Pseudomonas aeruginosa were investigated in C5-deficient strains of mice with different genetic backgrounds. We studied pulmonary clearance and cell responses after aerosol exposure to P. aeruginosa in C5-deficient B10.D2/oSnJ and DBA/2J mice and their closest C5-sufficient counterparts, B10.D2/nSnJ and DBA/1J mice. Different patterns of lung clearance and pulmonary cell responses were found for the two C5-deficient strains. C5-deficient B10.D2/oSnJ mice showed defective lung clearance of P. aeruginosa 4 h after challenge compared with C5-sufficient B10.D2/nSnJ animals. This finding was associated with a decreased number of polymorphonuclear leukocytes recruited into the airways during the same time. Interestingly, C5-deficient DBA/2J mice recruited higher numbers of polymorphonuclear leukocytes than did C5-sufficient DBA/1J mice by 4 h after aerosolization. Nevertheless, lung clearance of P. aeruginosa in DBA/2J mice was not as effective as in C5-sufficient DBA/1J mice, suggesting that other functions of C5 besides chemotaxism could be involved. Lung clearance of P. aeruginosa was also investigated in C5-deficient and -sufficient hybrids sharing the same genetic background (DBA/2J X B10.D2). The results suggested that murine lung clearance of P. aeruginosa is markedly affected by lack of C5 in a specific genetic background (B10.D2).

Aerosols↗
PubMed1990

Quantitative genetic background effects on the Antennapaedia phenotype in Drosophila melanogaster.

Genetic background variation influencing expression of the Antennapaedia homeotic phenotype was examined by crossing the Antp73b allele of the Antennapaedia locus reciprocally into seven isogenically derived wild type strains of Drosophila melanogaster and their genetically heterogeneous parent strain, Dover. The parent Antp73b strain's Antennapaedia phenotype shows a small patch of untransformed antennal tissue remaining on the homeotic femur. The size of this patch was used as an assay for background variation influencing expression of the Antp73b homeotic mutation. Patch size varied approximately six-fold across the different genetic backgrounds. Effects of maternal parent, sex, and sex-linkage were also observed.

Animals↗
PubMed1989

Phenotypes of rotavirus reassortants depend upon the recipient genetic background.

We have previously characterized the biological and immunological properties of a simian rotavirus SA11 variant (4F) with an altered genome segment 4. The SA11-4F variant formed large plaques in the presence of protease, formed small clear plaques in the absence of protease, and grew to high titer in the presence of protease when compared to our standard wild type (SA11 clone 3). To determine the genome segment of the rotavirus SA11 variant 4F that encoded the unique protease-associated phenotypes of the variant, reassortants were generated that segregated the outer capsid genes of 4F onto a genetic background derived from either the bovine rotavirus B223 or our standard SA11 wild type (clone 3), both of which have contrasting protease-associated phenotypes. The parental and reassortant viruses were examined to determine which genes from the 4F variant encoded the ability (i) to form large plaques in the presence of protease, (ii) to form small clear plaques in the absence of exogenous protease, and (iii) to grow to significantly higher titer in the presence of protease. These phenotypes could be transferred to a clone 3 genetic background by a single genome segment from the 4F variant segment 4. However, in the 4F/B223 reassortants a different and unexpected situation was found. On a B223 genetic background the same phenotypes segregated with a combination of a minimum of two 4F genome segments, segments 4 and 9. These results indicate that the recipient genetic background onto which the genes of a donor rotavirus are reassorted can affect the phenotypes conferred by the presence of the donor segments. Thus, the results of segregation mapping experiments using reassortant viruses should be interpreted with caution.

Cell Line↗
PubMed1985

Influence of the genetic background on cell division and cell lysis: behaviour of different Escherichia coli strains carrying the ts-52 or the ftsA-3 mutation.

The analysis of Escherichia coli strains harbouring division mutations, namely the ts-52 or the ftsA-3 division alleles, in different genetic backgrounds showed that treatment with chloramphenicol in cells incubated at the restrictive temperature induced either cell lysis (ts-52 and ftsA-3 in MC-6 genetic background) or cell division (ts-52 in OV-2 genetic background). This chloramphenicol treatment of ftsA-3 filaments (previously designated at divA) does not induce cell division but does induce cell lysis.

Alleles↗
PubMed1989

Genotype-by-environment and epistatic interactions in Drosophila melanogaster: the effects of Gpdh allozymes, genetic background and rearing temperature on larval developmental time and viability.

The possible role of temperature as a component of natural selection generating the latitudinal clines in Gpdh allele frequencies in natural populations of Drosophila melanogaster was examined. Effects of rearing temperature (16 degrees, 22 degrees and 29 degrees) and of Gpdh allozymes (S and F) on larval developmental time and viability were measured. Eight genetic backgrounds from each of three populations (continents) were used to assess the generality of any effects. Analyses of variance indicated significant temperature effects and allozyme-by-genetic background interaction effects for both characters. Viability showed significant genetic background effects, as well as significant temperature-by-allozyme and temperature-by-allozyme-by-population interactions. In general, the S/S genotype was significantly lower in viability than the F/F and F/S genotypes at extreme temperatures (16 degrees and 29 degrees), with no significant differences at 22 degrees. However, each population had a slightly different pattern of viability associated with temperature, and only the Australian population showed a pattern that could contribute to the observed cline formation. Although the same two interactions were not significant for developmental time, examination of the means showed that the S/S genotype had a slightly faster rate of development at 16 degrees than the F/F genotype in all populations (by an average of 0.25 day or 1.1%). The low temperature effect on developmental time is consistent with the clines observed in nature, with the S allele increasing in frequency with higher latitudes. The results for both viability and developmental time are consistent with the interpretation of Gpdh as a minor polygene affecting physiological phenotypes, as indicated by previous work with adult flight metabolism. Finally, it is proposed that the temperature-dependent antagonistic effects of the allozymes on viability vs. developmental time and flight metabolism may be the underlying force giving rise to the worldwide polymorphism.

Analysis of Variance↗
PubMed1992

[A case-control study on the relationship between smoking and genetic background and lung cancer].

A case-control study on the relationship between smoking and genetic background and lung cancer was carried out. The cases (probund) were death cases of lung cancer diagnosed between 1984 and 1986 in Quanshan County, and the controls were healthy people at the same period. Cases and controls were 1:1 in match with sex, age and residence. 196 pairs were so matched. The results were adjusted for smoking habit and family history of lung cancer using conditionally logistic regression model. There were significant differences shown in quantity of smoking (packet/year) (beta = 0.070 9) and age to start (years) (beta = -0.055 6) between cases and controls. There were also significant differences in history of lung cancer of first and second relatives (living together or not) between cases and controls. The positive interaction between smoking habit and genetic background of lung cancer was also found.

Case-Control Studies↗
PubMed1986

The influence of genetic background and the homologous chromosome 17 on t-haplotype transmission ratio distortion in mice.

Transmission ratio distortion is a characteristic of complete t-haplotypes, such that heterozygous males preferentially transmit the t-haplotype bearing chromosome 17 to the majority of their progeny. At least two genes contained within the t-haplotype have been identified as being required for such high transmission ratios. In this study we examine the effects of the genetic background and the chromosome homologous to the t-haplotype on transmission ratio distortion. We use two different congenic lines: BTBRTF/Nev.Ttf/t12, in which the t12 haplotype has a transmission ratio of 52%, and C3H/DiSn.Ttf/t12, in which the t12 haplotype has a transmission ratio of 99%. By intercrossing these two strains to produce reciprocal F1 and F2 generations, we have isolated the effects of the homologous chromosome 17 from the effects of the genetic background. We demonstrate that both the homologous chromosome and the genetic background have profound effects on t-haplotype transmission ratio distortion. Furthermore, it is evident that the t-haplotype transmission ratio behaves as a quantitative character rather than an intrinsic property of t-haplotypes.

Analysis of Variance↗
PubMed1978

Genetic background of Fuchs' heterochromic cyclitis.

We studied the genetic background of 24 patients with Fuchs' heterochromic cyclitis (FHC). Each was given a careful eye examination which included family history and serological determination of HLA antigens. Two families each had 2 cases of FHC in the same family; in addition an ancestor in the second family possibly had FHC; in both families one healthy member had simple heterochromia. One patient with FHC had congenital uveal coloboma, one pigmentary retinal dystrophy, and four had cysts of the ciliary body. The frequencies of all HLA antigens in patients with FHC compared well with the frequencies in the controls. In a family in which HLA haplotypes could be derived, the patients with FHC showed different HLA haplotypes. We conclude that FHC has a hereditary basis but its immunological component is not genetically associated with the HLA system.

Adolescent↗
PubMed1989

Impact of the genetic background of transgenic mice upon the formation and timing of choroid plexus papillomas.

Transgenic mice harboring the SV40 large T antigen gene in a C57B1/6J genetic background (SV11) first express this gene at 1-2 weeks of age, develop papillomas of the choroid plexus by 80-90 days, and die within 125 days after birth. Transgenic mice harboring the same transgene in a (SV11-C57Bl/6J x NZW/lacJ) F1 genetic background express considerably lower levels of the transgene mRNA at comparable times after birth. As a consequence, tumor development and death are delayed. The NZW mice appear to contribute a dominant negative regulator for the expression of the SV40 large T antigen transgene, which in turn has a dramatic effect upon the time of appearance of tumors and the death of these transgenic animals.

Animals↗
PubMed2026

Genetic background influences developmental airway smooth muscle program and susceptibility to airway hyperresponsiveness in mice.

Airway structural remodeling and hyperresponsiveness (AHR), hallmarks of asthma, are influenced by genetic variations and adverse exposures. While intrauterine perturbations in lung development have been linked to adult pulmonary disease, the developmental origins of these abnormalities remain poorly understood. Here, we provide evidence of genetic background playing a key role in this process. Using A/J and C57BL/6J mice known for their distinct susceptibility to AHR, we show that A/J embryos selectively develop an aberrant airway smooth muscle (SM) program and AHR in adulthood when exposed transiently to a vitamin A/retinoic acid (RA)-disrupted intrauterine environment in vivo by maternal BMS493 administration. Single-nucleus multiomics identified a mesenchymal cell population overactivating TGF-β targets in response to BMS493 selectively in A/J lungs. These cells, localized to sites of airway SM initiation and p-SMAD2- and -3, exhibited robust BMS493-mediated upregulation of SMAD2/3 targets, including regulators of SM program Pdgfra and Tnc. Functional analyses in vivo and cultured lungs showed aberrant SM formation in areas of overactive TGF-β of BMS493-exposed lungs. These abnormalities were prevented by inhibiting TGF-β signaling in utero in RA-deficient embryos. These findings underscore how distinct genetic backgrounds respond to intrauterine perturbations that program airway structure and function, with potential lasting consequences in postnatal pulmonary function.

Animals↗
PubMed1991

Influence of the genetic background and carrier protein on the antibody response to GnRH.

A vaccine against the gonadotropin releasing hormone (GnRH) is being developed as an immunological method for the treatment of prostatic enlargement. The work described here was aimed at investigating the influence of the genetic background on immune responses to GnRH conjugated to diphtheria toxoid (DT). Mice of different strains were injected with the conjugate and the antibody levels against GnRH and DT quantitated in order to examine the effect of genetic background on immune responses to the hapten and the carrier. All immunized animals produced antibodies to DT. Anti-GnRH antibodies were generated by all strains of mice except 129. The low anti-GnRH response in the 129 strain mice did not appear to be MHC-linked, as C57BL/6 mice, which bear the same MHC haplotype as 129 mice, were able to generate a strong anti-GnRH response. The non-responsiveness to the hapten (GnRH) in 129 strain mice was overcome by the use of an 'alternate carrier' approach.

Animals↗
PubMed1986

Genetic background of high incidence of spontaneous tumors in BDX rats.

Genetic background of high incidence of spontaneous tumors in BDX rats was investigated with respect to susceptibility to physical or chemical agents and immune response. Percentages of colony forming ability of normal embryo fibroblasts from BDX rats after exposure to various doses of ultraviolet (UV) light, X-rays and Mitomycin C were almost identical to those of cells from control F344 rats. Furthermore, BDX rats showed similar level of rosette forming cells, blastogenic response, and plaque forming cell (PFC) response as compared with WKA rats used as a control, although BDX rats showed higher natural killer (NK) cell activity. These results indicate that high incidence of spontaneous tumors in BDX rats is not due to some defects in DNA repair or immune response. In 3 methylcholanthrene (MCA) carcinogenesis, however, BDX rats developed tumors very early; the mean latency periods for development of MCA-induced tumors were 135 days in BDX rats and 256 days in F344 rats. Measurement of the inducibility of specific aryl hydrocarbon hydroxylase (AHH) activity in liver microsomes revealed that BDX rats showed higher inducibility than F344 rats: the inducibilities were 23.7 in BDX rats and 5.7 in F344 rats. Higher inducibility of AHH in BDX rats seemed to be parallel to earlier development of tumors in MCA-carcinogenesis in the rats. Thus, it is most likely that high incidence of spontaneous tumors in BDX rats is due to high susceptibility to some chemical carcinogens which may be contained in foods or drinking water in a small dose.

Animals↗
PubMed2026

Research note: Genetic background influences the relationship between age at first egg and long-term egg production in layers.

Age at first egg (AFE) is a key selection criterion in layers breeding. With the laying cycle being extended to 100 weeks, the relationship between AFE and long-term productivity and egg quality should be evaluated to ensure that selection for AFE aligns with current breeding objectives. In this study, Beijing-You chickens and White Leghorns were used to generate purebreds and crossbreds. Egg-laying performance was recorded including AFE, egg number and cumulative egg number at different stages from onset till 100 weeks, and egg quality traits at 32, 54, 72, 86, and 100 weeks. Genetic correlations were estimated, both in the combined population of purebreds and crossbreds and within each genetic group. In the combined population, a positive genetic correlation was observed between AFE and cumulative egg number till 100 weeks. Age-dependent genetic correlations between egg number at different stages and AFE further revealed that extremely early-maturing hens showed initial production advantages, but these advantages diminished at later stages. Importantly, the genetic and phenotypic correlations between AFE and egg quality traits were weak, with correlation coefficients ranging from -0.18 to 0.35. Within each genetic group, the relationships between AFE and egg production also showed consistent age-dependent patterns. For the long-term production targets, optimal AFE seems to differ by genetic backgrounds. White Leghorns showed higher egg production with earlier maturity, whereas in Beijing-You chickens, maintaining AFE at approximately 140-189 days appeared to be more favorable. Overall, these findings demonstrated that earlier AFE does not ensure higher egg production at extended laying cycles and has negligible influence on egg quality, highlighting the importance of optimizing AFE according to genetic background.

Age at first egg↗
PubMed1985

Effect of splenectomy on the development of experimental autoimmune encephalomyelitis in rats with different genetic background.

We studied the effect of total or partial splenectomy on experimental autoimmune encephalomyelitis (EAE) development in rats with different genetic background after immunization with guinea pig basic encephalitogenic protein in Freund's complete adjuvant. The operations did not affect some strains with a high susceptibility to EAE but may have reduced the EAE development in the Fischer strain, which shows only a weak susceptibility. In some hybrids and backcrosses, but not in others, splenectomy resulted in a clear-cut reduction of neurological signs of EAE. This effect may be ascribed to the elimination of contrasuppressive cell populations.

Animals↗