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Tamara J Phillips

Publications and source records attributed to Tamara J Phillips.

At least 19 recordsLinked to original sources
PubMed2006

GABAB receptor stimulation accentuates the locomotor effects of morphine in mice bred for extreme sensitivity to the stimulant effects of ethanol.

Mice selectively bred for divergent sensitivity to the locomotor stimulant effects of ethanol (FAST and SLOW) also differ in their locomotor response to morphine. The GABA(B) receptor has been implicated in the mediation of locomotor stimulation to both ethanol and morphine, and a reduction in ethanol-induced stimulation has been found with the GABA(B) receptor agonist baclofen in FAST mice. We hypothesized that GABA(B) receptor activation would also attenuate the locomotor stimulant responses to morphine in these mice. In order to test this hypothesis, baclofen was administered to FAST-1 and FAST-2 mice 15 min prior to morphine, and activity was recorded for 30 min. Baclofen attenuated stimulation to 32 mg/kg morphine in FAST-1 mice, but only at a dose that also reduced saline activity. There was no stimulant response to 32 mg/kg morphine in FAST-2 mice, or to 16 mg/kg or 48 mg/kg morphine in FAST-1 mice, but the combination of baclofen with these morphine doses accentuated locomotor activity. Therefore, it appears that GABA(B) receptor activation is not a common mechanism for the locomotor stimulant responses to ethanol and morphine in FAST mice; however, these data suggest that GABA(B) receptor activation may instead enhance some of the behavioral effects of morphine.

Animals↗
PubMed2006

Toward understanding the genetics of alcohol drinking through transcriptome meta-analysis.

Much evidence from studies in humans and animals supports the hypothesis that alcohol addiction is a complex disease with both hereditary and environmental influences. Molecular determinants of excessive alcohol consumption are difficult to study in humans. However, several rodent models show a high or low degree of alcohol preference, which provides a unique opportunity to approach the molecular complexities underlying the genetic predisposition to drink alcohol. Microarray analyses of brain gene expression in three selected lines, and six isogenic strains of mice known to differ markedly in voluntary alcohol consumption provided >4.5 million data points for a meta-analysis. A total of 107 arrays were obtained and arranged into six experimental data sets, allowing the identification of 3,800 unique genes significantly and consistently changed between all models of high or low amounts of alcohol consumption. Several functional groups, including mitogen-activated protein kinase signaling and transcription regulation pathways, were found to be significantly overrepresented and may play an important role in establishing a high level of voluntary alcohol drinking in these mouse models. Data from the general meta-analysis was further filtered by a congenic strain microarray set, from which cis-regulated candidate genes for an alcohol preference quantitative trait locus on chromosome 9 were identified: Arhgef12, Carm1, Cryab, Cox5a, Dlat, Fxyd6, Limd1, Nicn1, Nmnat3, Pknox2, Rbp1, Sc5d, Scn4b, Tcf12, Vps11, and Zfp291 and four ESTs. The present study demonstrates the use of (i) a microarray meta-analysis to analyze a behavioral phenotype (in this case, alcohol preference) and (ii) a congenic strain for identification of cis regulation.

Alcohol Drinking↗
PubMed2006

Ethanol-related traits in mice selectively bred for differential sensitivity to methamphetamine-induced activation.

Acute drug stimulation has been proposed to be an endophenotype for drug abuse. The authors previously reported the short-term selective breeding of lines of mice for low (LMACT) and high (HMACT) stimulation to methamphetamine (MA). These mice were used to examine whether common genes influence the locomotor response to MA and ethanol. Additionally, the authors tested these mice for ethanol drinking, locomotor sensitization, and clearance. LMACT mice were less stimulated by ethanol and consumed more ethanol than HMACT mice, but the lines did not differ in ethanol-induced sensitization. A small difference in ethanol clearance rate (0.1 mg/ml/h) likely had little impact on behavior. Some common genes may influence the locomotor response to MA and ethanol, as well as ethanol drinking.

Alcohol Drinking↗
PubMed2006

Alcohol-related genes: contributions from studies with genetically engineered mice.

Since 1996, nearly 100 genes have been studied for their effects related to ethanol in mice using genetic modifications including gene deletion, gene overexpression, gene knock-in, and occasionally by studying existing mutants. Nearly all such studies have concentrated on genes expressed in brain, and the targeted genes range widely in their function, including most of the principal neurotransmitter systems, several neurohormones, and a number of signaling molecules. We review 141 published reports of effects (or lack thereof) of 93 genes on responses to ethanol. While most studies have focused on ethanol self-administration and reward, and/or sedative effects, other responses studied include locomotor stimulation, anxiolytic effects, and neuroadaptation (tolerance, sensitization, withdrawal). About 1/4 of the engineered mutations increase self-administration, 1/3 decrease it, and about 40% have no significant effect. In many cases, the effects on self-administration are rather modest and/or depend on the specific experimental procedures. In some cases, genes in the background strains on which the mutant is placed are important for results. Not surprisingly, review of the systems affected further supports roles for serotonin, gamma-aminobutyric acid, opioids and dopamine, all of which have long been foci of alcohol research. Novel modulatory effects of protein kinase C and G protein-activated inwardly rectifying K+ (GIRK) channels are also suggested. Some newer research with cannabinoid systems is promising, and has led to ongoing clinical trials.

Alcoholism↗
PubMed2006

Delay discounting predicts behavioral sensitization to ethanol in outbred WSC mice.

BACKGROUND: Alcoholic individuals discount the value of future rewards more steeply than social drinkers, which is viewed as symptomatic of higher levels of impulsivity. However, the mechanisms underlying this difference are unknown. This study examined 2 hypotheses about the relationship between discounting and ethanol's effects in mice: (1) steep discounters are less sensitive to the initial stimulant-like effects of ethanol and (2) steep discounters exhibit greater behavioral adaptation to stimulant effects with repeated ethanol exposure. METHODS: An adjusting amount procedure was used to assess discounting as a function of delay in ethanol-naïve genetically heterogeneous WSC mice. Mice chose between a small amount of sucrose solution delivered immediately and 19.5 microL delivered following a delay (0, 2, 4, 8, or 12 seconds, varied between sessions). Within sessions, the amount (microL) of immediate sucrose was adjusted until animals became indifferent between the immediate and specific delayed reward. Hyperbolic discount functions were fitted to quantify the degree of delay discounting. Then, in a within-subjects design over 13 days, mice received a pattern of daily injections of saline or ethanol, and after certain treatments their locomotor activity was assessed for 15 minutes. RESULTS: Animals with steeper discount functions (greater impulsivity) tended to exhibit less locomotor stimulation on their initial exposure to ethanol. However, steeper discounting was positively associated with increases in locomotor activity after repeated exposure (sensitization), indicating that steep discounters showed higher levels of sensitization to the stimulating effects of ethanol. CONCLUSIONS: These results suggest 2 behavioral effects of ethanol, associated with an increased risk for alcohol abuse, that are associated with variations in delay discounting.

Adaptation, Psychological↗
PubMed2005

Naloxone does not attenuate the locomotor effects of ethanol in FAST, SLOW, or two heterogeneous stocks of mice.

RATIONALE: Previous studies suggest that some behavioral effects of ethanol and morphine are genetically correlated. For example, mice bred for sensitivity (FAST) or insensitivity (SLOW) to the locomotor stimulant effects of ethanol differ in their locomotor response to morphine. OBJECTIVE: To evaluate a possible common mechanism for these traits, we examined the effect of naloxone, an opioid receptor antagonist, on ethanol- and morphine-induced locomotion in FAST and SLOW mice, as well as on ethanol-induced locomotion in two heterogeneous stocks of mice. METHOD: In experiments 1 and 2, naloxone was given to FAST and SLOW mice 30 min prior to 2 g/kg ethanol or 32 mg/kg morphine, and locomotor activity was measured for 15 min (ethanol) or 30 min (morphine). In experiments 3 and 4, naloxone was administered 30 min prior to 1.25 g/kg ethanol, and locomotor activity was assessed in FAST mice and in a heterogeneous line of mice [Withdrawal Seizure Control (WSC)]. Experiment 5 assessed the effect of naloxone on ethanol-induced stimulation in outbred National Institutes of Health (NIH) Swiss mice. RESULTS: There was no effect of naloxone on the locomotor response to ethanol in FAST, SLOW, WSC, or NIH Swiss mice. However, naloxone did significantly attenuate the locomotor effects of morphine in FAST and SLOW mice. CONCLUSIONS: These results suggest that a common opioidergic mechanism is not responsible for the correlated locomotor responses to ethanol and morphine in FAST and SLOW mice, and that activation of the endogenous opioid system is not critical for the induction of ethanol-induced alterations in activity.

Animals↗
PubMed2005

Gene expression differences in mice divergently selected for methamphetamine sensitivity.

In an effort to identify genes that may be important for drug-abuse liability, we mapped behavioral quantitative trait loci (bQTL) for sensitivity to the locomotor stimulant effect of methamphetamine (MA) using two mouse lines that were selectively bred for high MA-induced activity (HMACT) or low MA-induced activity (LMACT). We then examined gene expression differences between these lines in the nucleus accumbens, using 20 U74Av2 Affymetrix microarrays and quantitative polymerase chain reaction (qPCR). Expression differences were detected for several genes, including Casein Kinase 1 Epsilon (Csnkle), glutamate receptor, ionotropic, AMPA1 (GluR1), GABA B1 receptor (Gabbr1), and dopamine- and cAMP-regulated phosphoprotein of 32 kDa (Darpp-32). We used the www.WebQTL.org database to identify QTL that regulate the expression of the genes identified by the microarrays (expression QTL; eQTL). This approach identified an eQTL for Csnkle on Chromosome 15 (LOD = 3.8) that comapped with a bQTL for the MA stimulation phenotype (LOD = 4.5), suggesting that a single allele may cause both traits. The chromosomal region containing this QTL has previously been associated with sensitivity to the stimulant effects of cocaine. These results suggest that selection was associated with (and likely caused) altered gene expression that is partially attributable to different frequencies of gene expression polymorphisms. Combining classical genetics with analysis of whole-genome gene expression and bioinformatic resources provides a powerful method for provisionally identifying genes that influence complex traits. The identified genes provide excellent candidates for future hypothesis-driven studies, translational genetic studies, and pharmacological interventions.

Animals↗
PubMed2005

Genetic correlational analyses of ethanol reward and aversion phenotypes in short-term selected mouse lines bred for ethanol drinking or ethanol-induced conditioned taste aversion.

Short-term selective breeding created mouse lines divergent for ethanol drinking (high drinking short-term selected line [STDRHI], low drinking [STDRLO]) or ethanol-induced conditioned taste aversion (CTA; high [HTA], low [LTA]). Compared with STDRLO, STDRHI mice consumed more saccharin and less quinine, exhibited greater ethanol-induced conditioned place preference (CPP), and showed reduced ethanol stimulation and sensitization under some conditions; a line difference in ethanol-induced CTA was not consistently found. Compared with LTA, HTA mice consumed less ethanol but were similar in saccharin consumption, sensitivity to ethanol-induced CPP, and ethanol-induced locomotor stimulation and sensitization. These data suggest that ethanol drinking is genetically associated with several reward-and aversion-related traits. The interpretation of ethanol-induced CTA as more genetically distinct must be tempered by the inability to test the CTA lines beyond Selection Generation 2.

Alcohol Drinking↗
PubMed2005

The syntaxin binding protein 1 gene (Stxbp1) is a candidate for an ethanol preference drinking locus on mouse chromosome 2.

BACKGROUND: We previously mapped a quantitative trait locus (QTL) for ethanol preference drinking to mouse chromosome 2 (mapped with high confidence, LOD = 15.5, p = 3 x 10(-16)). The specific gene(s) in the QTL interval responsible for phenotypic variation in ethanol preference drinking has not been identified. METHODS: In the current study, we investigated the association of the syntaxin binding protein 1 gene (Stxbp1) with ethanol preference drinking and other ethanol traits using a panel of B6 x D2 (BXD) recombinant inbred (RI) strains derived from the C57BL/6J (B6) and DBA/2J (D2) inbred mouse strains. Confirmation analyses for ethanol consumption and withdrawal were performed using a large B6D2 F2 cross, short-term selected lines derived from the B6 and D2 progenitor strains, and standard inbred strains. RESULTS: BXD RI strain analysis detected provisional associations between Stxbp1 molecular variants and ethanol consumption, as well as severity of acute ethanol withdrawal, ethanol-conditioned taste aversion, and ethanol-induced hypothermia. Confirmation analyses using three independent genetic models supported the involvement of Stxbp1 in ethanol preference drinking but not in ethanol withdrawal. CONCLUSIONS: Stxbp1 encodes a Sec1/Munc18-type protein essential for vesicular neurotransmitter release. The present study provides supporting evidence for the involvement of Stxbp1 in ethanol preference drinking.

Alcohol Drinking↗
PubMed2005

Mice deficient in corticotropin-releasing factor receptor type 2 exhibit normal ethanol-associated behaviors.

BACKGROUND: Stress is believed to influence alcohol use and relapse in alcoholics. Animal studies suggest an interaction between corticotropin-releasing factor (CRF) and its receptors and the behavioral effects and consumption of alcohol. The objective of these studies was to examine the effect of corticotropin-releasing factor receptor type 2 (CRF2) on ethanol consumption, conditioned taste aversion, sedation, and hypothermia. METHODS: CRF2-null mutant or knock-out (KO), and wild-type (WT) mice were used to assess consumption of increasing concentrations of ethanol in a two-bottle, 24-hr test and during daily limited-access sessions. Ethanol-induced conditioned taste aversion (CTA), loss of righting reflex (LORR), hypothermia, and ethanol metabolism kinetics were also examined in the CRF2 KO and WT mice. RESULTS: CRF2 KO mice did not differ from WT mice in sensitivity to ethanol-induced CTA, LORR, hypothermia, or ethanol metabolism kinetics. There was no genotypic difference in ethanol intake or preference in the 24-hr, two-bottle choice procedure, and only modestly increased [corrected] consumption of the 7.5 and 10% ethanol solutions in KO versus WT mice in the limited-access procedure. CONCLUSIONS: CRF2 deficiency had little effect on several ethanol-associated behaviors in CRF2-null mutant compared with WT mice, suggesting that this receptor does not have a primary role in modulating these behaviors. Evidence of a role for this receptor in neural circuits subserving stress-coping behaviors suggest that future studies should focus on the role of endogenous CRF2 in ethanol-associated behaviors in mice that are stressed or withdrawing from dependence on ethanol.

Animals↗
PubMed2005

Neurosteroid modulators of GABA(A) receptors differentially modulate Ethanol intake patterns in male C57BL/6J mice.

BACKGROUND: Allopregnanolone (ALLO) and structurally related endogenous neurosteroids are potent modulators of gamma-aminobutyric acid A (GABA(A)) receptor function at physiologically relevant concentrations. Accumulating evidence implicates a modulatory role for ALLO in behavioral processes underlying ethanol self-administration, discrimination, and reinstatement. The purpose of this study was to evaluate the impact of exogenous neurosteroid challenges with the agonist ALLO and the partial agonist/antagonist epipregnanolone (EPI) on the microarchitecture of ethanol drinking patterns. METHODS: Male C57BL/6J mice were initiated to consume an unsweetened 10% v/v ethanol solution (10 E) by a saccharin fading procedure during daily 2-hr limited-access sessions beginning 1-hr after dark-phase onset. Cumulative lick responses were recorded for 10 E and water by lickometer circuits. After establishing 10 E intake baselines, mice were habituated to vehicle injection (VEH; 20% w/v beta-cyclodextrin ip), and then were treated with either VEH or neurosteroid immediately before the drinking session. Each mouse received a series of ALLO doses (3.2, 10, 17, and 24 mg/kg) alone and EPI doses (0.15, 1, 3, and 10 mg/kg) alone in a counterbalanced within-group design. RESULTS: The GABA(A) receptor-positive modulator ALLO dose-dependently modulated overall ethanol intake throughout the 2-hr session with the 3.2 mg/kg dose eliciting a significant increase, whereas the 24 mg/kg dose produced a significant suppression of ethanol intake versus VEH pretreatment. ALLO-evoked alterations in intake corresponded to significant, dose-dependent alterations in bout frequency and interbout interval. ALLO also elicited robust, dose-dependent elevations in 10 E licks during the initial 5 min of access but subsequently produced in a dose-dependent suppression of 10 E licks during session minutes 20-80. In contrast, the partial agonist/antagonist neurosteroid EPI exhibited no influence on any consumption parameter evaluated. CONCLUSIONS: The present findings suggest that GABA(A) receptor-active neurosteroids may modulate the regulatory processes that govern the onset, maintenance, and termination of drinking episodes. The differential influence of ALLO and EPI on ethanol intake patterns may reflect an alteration in GABA-ergic inhibitory tone that is likely due to each neurosteroid's pharmacological profile at GABA(A) receptors. Manipulation of endogenous ALLO may prove a useful strategy for diminishing excessive intake and protecting against the loss of regulatory control over drinking.

Alcohol Drinking↗
PubMed2005

The effect of fostering on the genetic expression of locomotor sensitivity to alcohol.

Steps were taken to eradicate endemic mouse coronavirus from a colony that was part of a behavioral project characterizing the genetics of alcohol sensitivity. This behavioral study was conducted to determine whether changing the uterine or rearing environment (as is integral to common rederivation methods) would have a significant effect on the expression of the behavioral traits in question. Selected breeding pairs of the affected lines were divided into four treatment groups: 1) transfer of embryos to pseudopregnant B6D2F1 female mice, 2) fostering offspring to B6D2F1 dams, 3) fostering offspring to a different dam of the same line, and 4) offspring raised by the birth dam. Embryo transfers were successful only in one affected line. At approximately 50 days of age, the offspring were tested for locomotor behavior after intraperitoneal administration of ethanol or normal saline. There were no statistically significant effects of embryo transfer on the ethanol phenotype (ethanol-induced locomotor depression). Fostering significantly reduced the stimulant response to ethanol of only one mouse line selectively bred for high sensitivity to ethanol-induced stimulation, although the stimulant response of the fostered groups was still quite robust. Overall, the results of this study showed that eradication efforts involving fostering of offspring have a modest impact on the stimulant response to ethanol, but there were insufficient data to draw conclusions regarding the use of embryo transfer.

Animals↗
PubMed2004

Corticotropin-releasing factor overexpression decreases ethanol drinking and increases sensitivity to the sedative effects of ethanol.

RATIONALE: Corticotropin-releasing factor (CRF) may play a significant role in drug and alcohol abuse. OBJECTIVE: To evaluate the role of CRF in these processes, we examined several ethanol (EtOH) related behaviors in mice that carry a transgene that causes overexpression of CRF. METHODS: We examined voluntary EtOH drinking, loss of the righting reflex (LORR), EtOH-induced conditioned taste aversion (CTA), and EtOH clearance in littermate transgenic (TG) and non-transgenic (non-TG) mice. In addition, because preliminary results indicated that age exacerbated differences in EtOH consumption between the two genotypes, we performed a cross-sectional and longitudinal evaluation of this trait at two ages ( approximately 100 and 200 days old). RESULTS: We found that TG mice consumed significantly less EtOH and had a lower preference for EtOH-containing solutions compared with their non-TG littermates. We also found that the older drug-naive TG mice drank less EtOH as compared with the younger mice of the same genotype; however, the same relationship did not exist for drug-naive non-TG mice. Prior experience in drinking EtOH when 100 days old led to decreased EtOH drinking when 200 days old in both genotypes. Duration of LORR was longer in the TG mice, EtOH-induced CTA was marginally greater in non-TG mice at the highest dose tested, and there were significant but small differences in EtOH clearance parameters. CONCLUSIONS: These data show that CRF overexpressing mice voluntarily consume less EtOH. This difference is associated with greater sensitivity to the sedative-hypnotic effects of EtOH, but not with increased sensitivity to the aversive effects of EtOH.

Aging↗
PubMed2003

The Edinger-Westphal-lateral septum urocortin pathway and its relationship to alcohol consumption.

Identifying and characterizing brain regions regulating alcohol consumption is beneficial for understanding the mechanisms of alcoholism. To this aim, we first identified brain regions changing in expression of the inducible transcription factor c-Fos in the alcohol-preferring C57BL/6J (B6) and alcohol-avoiding DBA/2J (D2) mice after ethanol consumption. Drinking a 5% ethanol/10% sucrose solution in a 30 min limited access procedure led to induction of c-Fos immunoreactivity in urocortin (Ucn)-positive cells of the Edinger-Westphal nucleus (EW), suppression of c-Fos immunoreactivity in the dorsal portion of the lateral septum (LS) of both strains of mice, and strain-specific suppression in the intermediate portion of the LS and the CA3 hippocampal region. Because the EW sends Ucn projections to the LS, and B6 and D2 mice differ dramatically in EW Ucn expression, we further analyzed the Ucn EW-LS pathway using several genetic approaches. We find that D2 mice have higher numbers of Ucn-immunoreactive processes than B6 mice in the LS and that consumption of ethanol/sucrose in the F2 offspring of a B6D2 intercross positively correlates with Ucn immunoreactivity in the EW and negatively correlates with Ucn immunoreactivity in the LS. In agreement with these findings, we find that alcohol-avoiding male B6.D2 Alcp1 line 2.2 congenic mice have lower Ucn immunoreactivity in the EW than male B6.B6 mice. Finally, we also find that HAP mice, selectively bred for high alcohol preference, have higher Ucn immunoreactivity in EW, than LAP mice, selectively bred for low alcohol preference. Taken together, these studies provide substantial evidence for involvement of the EW-LS Ucn pathway in alcohol consumption.

Alcohol Drinking↗
PubMed2003

Different data from different labs: lessons from studies of gene-environment interaction.

It is sometimes supposed that standardizing tests of mouse behavior will ensure similar results in different laboratories. We evaluated this supposition by conducting behavioral tests with identical apparatus and test protocols in independent laboratories. Eight genetic groups of mice, including equal numbers of males and females, were either bred locally or shipped from the supplier and then tested on six behaviors simultaneously in three laboratories (Albany, NY; Edmonton, AB; Portland, OR). The behaviors included locomotor activity in a small box, the elevated plus maze, accelerating rotarod, visible platform water escape, cocaine activation of locomotor activity, and ethanol preference in a two-bottle test. A preliminary report of this study presented a conventional analysis of conventional measures that revealed strong effects of both genotype and laboratory as well as noteworthy interactions between genotype and laboratory. We now report a more detailed analysis of additional measures and view the data for each test in different ways. Whether mice were shipped from a supplier or bred locally had negligible effects for almost every measure in the six tests, and sex differences were also absent or very small for most behaviors, whereas genetic effects were almost always large. For locomotor activity, cocaine activation, and elevated plus maze, the analysis demonstrated the strong dependence of genetic differences in behavior on the laboratory giving the tests. For ethanol preference and water escape learning, on the other hand, the three labs obtained essentially the same results for key indicators of behavior. Thus, it is clear that the strong dependence of results on the specific laboratory is itself dependent on the task in question. Our results suggest that there may be advantages of test standardization, but laboratory environments probably can never be made sufficiently similar to guarantee identical results on a wide range of tests in a wide range of labs. Interpretations of our results by colleagues in neuroscience as well as the mass media are reviewed. Pessimistic views, prevalent in the media but relatively uncommon among neuroscientists, of mouse behavioral tests as being highly unreliable are contradicted by our data. Despite the presence of noteworthy interactions between genotype and lab environment, most of the larger differences between inbred strains were replicated across the three labs. Strain differences of moderate effects size, on the other hand, often differed markedly among labs, especially those involving three 129-derived strains. Implications for behavioral screening of targeted and induced mutations in mice are discussed.

Acceleration↗
PubMed2003

The mapping of quantitative trait loci underlying strain differences in locomotor activity between 129S6 and C57BL/6J mice.

Performance in the open field and rotarod paradigms, two common assessments of locomotor function, have been demonstrated to be strain dependent in mice. In this study, eight significant quantitative trait loci (QTL) for behavior phenotypes in either the open field or rotarod paradigms were identified between the 129S6 (129/SvEvTac) and C57BL/6J strains. These strains were chosen for comparison because of their frequent use in the generation of mutant mice from gene-targeted, embryonic stem cells. Two of the QTLs for horizontal distance traveled are located on Chromosomes (Chrs) 1 and 12 and closely replicate the findings of other groups using different strains of mice. Rotarod performance was influenced in an oppositional manner by two separate QTLs on Chr 1 and 2. Additionally, examination of several different aspects of behavior in the open field revealed significant QTLs for average speed (Chr 12), duration (Chrs 2, 16, and 18), time spent in motion (Chr 16), vertical movements (rearing) (Chrs 6 and 12), and vertical time (rearing time) (Chrs 6 and 12). Our finding of independent QTLs for these topographic components of open field activity supports the idea that they are separate and distinct from total horizontal distance traveled and should be studied independently. The QTLs described in this study, in combination with our panel of polymorphic chromosomal markers for 129S6 and C57BL/6J strains, will be useful in assessing the potential epistatic effects of parental strain background on the phenotypes of genetically modified mice.

Animals↗