Comparative analysis of the anxiety-related behaviors in four inbred mice

An anxiety-related behavior is an emotional response of an organism, which is quantitatively measured by several behavioral paradigms. We employed two most frequently used behavioral tests, the open field and light-dark exploration, to comparatively analyze the anxiety-like behaviors in four inbred mice. For an accurate recording of movement, motion analysis software was developed that acquires a real-time video input to generate a behavioral path. Effects of the strains on the test results were evaluated by ANOVA with the Newman-Keuls post hoc comparison. Eight different behavioral indices, four from each tests, were grouped into two classes; the results of duration, center crossing, transition, rearing, and ambulation indicate strain differences of FVB/N>C57BL/6J>/=BALB/cA>/=CBA/N (I), while stretched-attend posture, peeping, and defecation show the tendency of FVB/N=C57BL/6J相似文献   

Diallel genetic analysis of the elements of paradise fish's (Macropodus opercularis L.) behavior in familiar and novel situations

Elements of the paradise fish's ethogram were recorded in 1 familiar and 3 different unfamiliar situations and the inheritance of these behavioral elements was investigated employing a five times replicated diallel cross between 3 inbred strains. A generalized Hayman Analysis of Variance and a Variance Covariance Analysis were performed to estimate genetic effects and parameters, such as, additive genetic variance, different sorts of dominance variance, reciprocal effects, direction and degree of dominance, ratio between the frequency of dominant and of recessive alleles, minimum number of effective factors and heritabilities, etc. Knowing the genetic architecture, we make inferences about the possible evolutionary past of the behavioral elements and explain why selection might favor certain types of paradise fish's behavior in particular circumstances. In several cases a possibility of "monogenic" inheritance emerged. We explain this finding and conclude that in a cross experiment where the inheritance of phenotypical units are investigated by employing only a few genetically different strains this result may be expected.     

Genetic analysis of susceptibility to isoniazid-induced seizures in mice

Four sets of recombinant inbred lines of mice have been used to analyze genetic differences in acute toxicity of the drug, isonicotinic acid hydrazide. Standard inbred strains, their F₁ hybrids and recombinant inbred strains were all challenged with a single dose of the drug. The percent mortality of the different groups was analyzed to estimate heritability and the number of genes affecting resistance. The data indicated that resistance factors were dominant, heritability was moderate (.25-.37), and more than one gene was involved in each of four different sets of recombinant inbred lines. Possible approaches for identifying and mapping individual genes affecting resistance are discussed.     

Quantitative genetic variation of metabolism in the nymphs of the sand cricket, Gryllus firmus, inferred from an analysis of inbred-lines

Compared with morphological and life history traits, quantitative genetic variation of metabolic and related traits in animals has been poorly studied. We used flow-through VCO(2) respirometry and simultaneous activity measurement on nymphs of the sand cricket (Gryllus firmus) from inbred lines to estimate broad-sense heritability of four metabolic variables. In addition, we measured a number of linear dimensions in the adults from the same inbred lines. There were significant multivariate effects of inbred lines for all traits and broad-sense heritability for physiological traits was 4.5%, 5.2%, 10.3% and 8.5% for average, resting, minimum and maximum CO(2) production in nymphs, respectively. Though the MANOVA indicated significant genetic variation among inbred lines in adult morphology, the broad-sense heritabilities were relatively low ranging from 0-18%. Our results indicate that the heritabilities of metabolic measures are large enough to potentially respond to selection.     

Unmethylated regions in the intergenic spacer of maize and teosinte ribosomal RNA genes

The restriction endonucleases Hpa II and Msp I were used to examine cytosine methylation in the ribosomal RNA genes (rDNA) of inbred lines of maize and species of teosinte. In all of the rDNAs examined, Msp I (not sensitive to mCpG) digestion yielded a distribution of lower molecular weight fragments indicative of multiple recognition sites. The majority of the rDNA arrays in an individual were inaccessible to Hpa II (sensitive to mCpG) cleavage, but a significant fraction (10–25%) was cleaved at least once by Hpa II into repeat unit length fragments (9.1 kbp). In some maize inbred lines, one or two additional fragment populations (less than 9.1 kbp in length) were also produced by Hpa II digestion. All of the unmethylated Hpa II sites mapped to the intergenic spacer (IGS), and the major unmethylated site was located approximately 800 bp 5 to the start of the 18S RNA coding sequence. An Eco RI polymorphism, present in the 26S gene of certain inbred lines and hybrids, was utilized to investigate the organization of unmethylated repeat units in the rDNA array. In double digest experiments with Hpa II/Eco RI, the fragments from repeat units with two Eco RI sites were sensitive to Hpa II digestion, whereas, the fragments from repeat units with a single Eco RI site were almost completely resistant to Hpa II digestion. Similar digestion patterns were also observed in Eco RII (sensitive to mCNG)/Eco RI digests. These results suggest that unmethylated and Eco RI polymorphic sites occur in the same repeat units.     

Distribution of the C1473G polymorphism in tryptophan hydroxylase 2 gene in laboratory and wild mice

The neurotransmitter serotonin is implicated in the regulation of various forms of behavior, including aggression, sexual behavior and stress response. The rate of brain serotonin synthesis is determined by the activity of neuronal‐specific enzyme tryptophan hydroxylase 2. The missense C1473G substitution in mouse tryptophan hydroxylase 2 gene has been shown to lower the enzyme activity and brain serotonin level. Here, the C1473G polymorphism was investigated in 84 common laboratory inbred strains, 39 inbred and semi‐inbred strains derived from wild ancestors (mostly from Eurasia) and in 75 wild mice trapped in different locations in Russia and Armenia. Among all the classical inbred strains studied, only substrains of BALB/c, A and DBA, as well as the IITES/Nga and NZW/NSlc strains were homozygous for the 1473G allele. In contrast to laboratory strains, the 1473G allele was not present in any of the samples from wild and wild‐derived mice, although the wild mice varied substantially in the C1477T neutral substitution closely linked to the C1473G polymorphism. According to these results, the frequency of the 1473G allele in natural populations does not exceed 0.5%, and the C1473G polymorphism is in fact a rare mutation that is possibly eliminated by the forces of natural selection.     

Emotionality, exploratory behavior, and locomotion in aging inbred strains of mice.

Two inbred strains of mice, C57BL/6J and DBA/2J, ranging in age from 2 to 38 months, were tested in an open field using the free exploration method. Scores were obtained for locomotor activity, exploratory behavior and emotionality. Strain differences were observed for all three variables. Beginning at late maturity (12 months), locomotor activity decreased with increasing age. Exploratory behavior was at a low level for DBA/2J mice at all ages. For C57BL/6J mice, exploratory behavior decreased significantly between 2 and 6 months and remained stable thereafter. Emotionality remained unchanged with advancing age for both strains of mice.     

Histocompatible chicken inbred lines: homogeneities in the major histocompatibility complex antigens of the GSP, GSN/1, PNP/DO and BM-C inbred lines assessed by hemagglutination, mixed lymphocyte reaction and skin transplantation.

Chicken inbred lines of the GSP, GSN/1, PNP/DO and BM-C have been established by selection of a specific allele at the B blood group locus (MHC B-G region) and other polymorphic loci through pedigree mating. To extend the potential of these inbred lines as experimental animals in Aves, we assessed the antigenic homogeneities of the MHC antigens by three immunological methods. Antigenic variations of red blood cells (RBCs) were surveyed in the inbred lines and a random-bred line (NG) derived from the Nagoya breed by using ten kinds of intact antisera produced in the inbred line of chickens against RBCs of a red junglefowl and hybrids. In the hemagglutination test, no individual variations were found within the inbred line at all, while all the ten antisera detected highly heterogeneous reactions in individuals of the NG. The reciprocal one-way mixed lymphocyte reactions gave constantly higher stimulation responses (P<0.01) between individual pairs from the inbred lines having different B alleles compared to pairs within the inbred line, while lower stimulation was observed between pairs of the GSP and GSN/1 inbred lines both having the B(21) allele. In reciprocal skin transplantation, the transplanted skingrafts within the inbred line and between individuals from the GSP and GSN/1 inbred lines survived more than 100 days, while all the skingrafts showed signs of rejection within 7 days among the inbred lines having different B alleles. The results obtained by the three practical methods coincidentally indicated that the individuals in the respective four inbred lines were histocompatible, and further, that the GSP and GSN/1 individuals were histocompatible.     

Maximum likelihood techniques for the mapping and analysis of quantitative trait loci with the aid of genetic markers

A method is presented to estimate the biometric parameters of a quantitative trait locus linked to a genetic marker when both loci are segregating in the F-2 generation of a cross between two inbred lines. The method, which assumes underlying normal distributions, is a combination of maximum likelihood and moments methods and uses the statistics of the genetic marker genotype samples for the quantitative trait to estimate the recombination frequency between the two loci and the means and variances of the genotypes of the quantitative trait locus. With this method, the genetic parameters of a locus affecting plant height linked to an electrophoretic marker for esterase were accurately estimated from a sample of 1596 F-2 progeny of a cross between two species of Lycopersicon (tomato). Linkage distance between the two loci was 38 map units and the effect of the quantitative trait locus was 1.6 phenotypic standard deviation units. Accurate estimates of the genetic parameters and linkage distance for populations of 2000 individuals simulated with a segregating codominant locus with an effect of 1.63 standard deviations linked to a genetic marker with .2 recombination were also derived by this method. The method is not effective in distinguishing between complete and partial linkage in samples of only 500 individuals or for quantitative loci with effects less than a phenotypic standard deviation. The method is more effective for codominant than for dominant loci.     

Localization of the growth hormone gene to the distal half of mouse chromosome 11

A DNA fragment size variant for the growth hormone gene, Gh, has been identified among inbred strains of mice. The inbred strains SM/J and CAST/Ei carry the less frequent allele Ghb and 11 other strains carry the Gha allele. Segregation analysis of data from two crosses involving SM/J and NZB/BINJ and a cross involving BALB/cJ and CAST/Ei confirmed the assignment of Gh to mouse chromosome 11 and placed the locus 2.6 +/- 1.8 map units distal to Erba (avian erythroblastosis oncogene A), a position consistent with the assignment of the Gh locus to the q22-q24 region of chromosome 17 on the human map. Segregation analysis also refined the location of Sparc (secreted acidic cysteine-rich glycoprotein) on mouse chromosome 11 to a position 16.7 +/- 4.2 map units proximal to Evi-2 (ecotropic viral integration site 2).     

Mapping quantitative trait loci using naturally occurring genetic variance among commercial inbred lines of maize (Zea mays L.)

Many commercial inbred lines are available in crops. A large amount of genetic variation is preserved among these lines. The genealogical history of the inbred lines is usually well documented. However, quantitative trait loci (QTL) responsible for the genetic variances among the lines are largely unexplored due to lack of statistical methods. In this study, we show that the pedigree information of the lines along with the trait values and marker information can be used to map QTL without the need of further crossing experiments. We develop a Monte Carlo method to estimate locus-specific identity-by-descent (IBD) matrices. These IBD matrices are further incorporated into a mixed-model equation for variance component analysis. QTL variance is estimated and tested at every putative position of the genome. The actual QTL are detected by scanning the entire genome. Applying this new method to a well-documented pedigree of maize (Zea mays L.) that consists of 404 inbred lines, we mapped eight QTL for the maize male flowering trait, growing degree day heat units to pollen shedding (GDUSHD). These detected QTL contributed >80% of the variance observed among the inbred lines. The QTL were then used to evaluate all the inbred lines using the best linear unbiased prediction (BLUP) technique. Superior lines were selected according to the estimated QTL allelic values, a technique called marker-assisted selection (MAS). The MAS procedure implemented via BLUP may be routinely used by breeders to select superior lines and line combinations for development of new cultivars.     

The evolution of social networks through the implementation of evidence-informed decision-making interventions: a longitudinal analysis of three public health units in Canada

Background

We studied the evolution of information-seeking networks over a 2-year period during which an organization-wide intervention was implemented to promote evidence-informed decision-making (EIDM) in three public health units in Ontario, Canada. We tested whether engagement of staff in the intervention and their EIDM behavior were associated with being chosen as information source and how the trend of inter-divisional communications and the dominance of experts evolved over time.

Methods

Local managers at each health unit selected a group of staff to get engage in Knowledge Broker-led workshops and development of evidence summaries to address local public health problems. The staff were invited to answer three online surveys (at baseline and two annual follow-ups) including name generator questions eliciting the list of the staff they would turn to for help integrating research evidence into practice. We used stochastic actor-oriented modeling to study the evolution of networks. We tested the effect of engagement in the intervention, EIDM behavior scores, organizational divisions, and structural dynamics of social networks on the tendency of staff to select information sources, and the change in its trend between year 1 and year 2 of follow-up.

Results

In all the three health units, and especially in the two units with higher levels of engagement in the intervention, the network evolved towards a more centralized structure, with an increasing significance of already central staff. The staff showed greater tendencies to seek information from peers with higher EIDM behavior scores. In the public health unit that had highest engagement and stronger leadership support, the engaged staff became more central. In all public health units, the engaged staff showed an increasing tendency towards forming clusters. The staff in the three public health units showed a tendency towards limiting their connections within their divisions.

Conclusions

The longitudinal analysis provided us with a means to study the microstructural changes in public health units, clues to the sustainability of the implementation. The hierarchical transformation of networks towards experts and formation of clusters among staff who were engaged in the intervention show how implementing organizational interventions to promote EIDM may affect the knowledge flow and distribution in health care communities, which may lead to unanticipated consequences.

     

A quantitative analysis of the genetics of resting blood lactic acid levels in mice

Resting blood lactate levels were measured in inbred mouse strains, their F(1), and several of their segregating generations to determine whether the level of lactic acid is influenced by genetic factors. The inbred strains in each of the two sets used differed significantly from one another for this character. Only one strain showed a significant sex difference. The data could not be fully analyzed because of the failure to fulfill Mather's first criterion for an adequate scale. Nonallelic interactions, in particular, additive x dominance and dominance x dominance, were found to influence the generation means. Genotype x environment interaction was detected and eliminated by log transformation. Negative heterosis was exhibited by all but one noninbred generation.-The data suggest that genes influencing the character are dispersed between the parental lines and that interactions are predominantly of the duplicate kind. A buffering system by which lactate levels are kept at a minimum is proposed.     

Ethological study of the social behavior of hybrid baboons betweenPapio anubis andP. hamadryas in free-ranging groups

The male-female and male-male interactions of hybrid baboons betweenPapio anubis andP. hamadryas were analyzed quantitatively in two free-ranging groups in the Awash Valley, Ethiopia. Morphologically, one group (the Kerrayu group) was closer to hamadryas, while the other (the Gorge group) was closer to anubis. The adult males were classified into four categories; i.e., leaders of one-male units, males in pair units (both in the Kerrayu group), males with a closer appearance to hamadryas, and males with an anubis-like appearance (both in the Gorge group). These categories coincided with the morphological gradient from hamadryas to anubis. Social behavior was described in terms of 53 kinds of behavioral elements identified. In both groups, the closer a male was to being hamadryas in morphology, the more frequent was the aggressive behavior it tended to address toward partner females. The patterns of male-female interactions were compared between one-male units and pair units in the Kerrayu group. In one-male units, females responded immediately with obedient behavior to the males' behavior of directing visual attention toward them. In pair units, females responded with affinitive or avoiding behavior to physical contact by males. The flow of male social behavior was resolved into transitions from one behavioral element to another, and the succession rates for all the observed transitions were independently computed within each male category. By comparing the principal pathways of the behavioral sequences between male categories, 31 “basic pathways” were identified, which were presumed to be common to bothP. anubis andP. hamadryas. The basic pathways were composed of four main behavioral categories, i.e.,Contact, Visual-spacing, Aggressive behavior toward females, andAppeasing behavior toward males. In one-male units, transitions fromVisual-spacing toAggressive behavior were clearly recognized, whereas the principal pathways in pair units lacked such transitions. The frequency distributions of behavioral elements among the above behavioral categories were compared among the four male categories. The more prevalent anubis characters were in morphology, the larger was the proportion thatContact behavior occupied in the total amount of social behavior. The more prevalent hamadryas characters were, the larger was the proportion thatVisual-spacing behavior occupied. The leaders of one-male units showed a higher percentage ofAggressive behavior than did males of the other three categories. A conspicuous difference was observed in the percentage ofAppeasing behavior between the Gorge and Kerrayu groups. It appeared that the high frequency ofAppeasing behavior among males in the Kerrayu group contributed to the spatial cohesion of this group. The similarities of morphology, principal pathways, and frequency distribution of behavior were calculated for every combination of the four male categories. The morphological similarities correlated best with the similarities of principal pathways. It is concluded that the sequential structure of the male social behavior was strongly correlated with the genetic background, while the frequency of social behavior itself was subject to factors other than innate behavioral tendencies, such as the characteristics of the social environment and social context.     

SSR analysis of genetic diversity among maize inbred lines adapted to cold regions of Japan

Information regarding diversity and relationships among breeding material is necessary for hybrid maize (Zea mays L.) breeding. Simple-sequence repeat (SSR) analysis of the 60 loci distributed uniformly throughout the maize genome was carried out for 65 inbred lines adapted to cold regions of Japan in order to assess genetic diversity among the inbred lines and to assign them to heterotic groups. The mean value (0.69) of the polymorphic-index content (PIC) for the SSR loci provided sufficient discrimination-ability for the assessment of genetic diversity among the inbred lines. The correlation between the genetic-similarity (GS) estimates and the coancestry coefficient was significant (r = 0.70). The average-linkage (UPGMA) cluster analysis and principal-coordinate analysis (PCOA) for a matrix of the GS estimates showed that the Northern flint inbred lines bred in Japan were similar to a Canadian Northern flint inbred line CO12 and a European flint inbred line F283, and that dent inbred lines bred in Japan were similar to BSSS inbred lines such as B73. These associations correspond to the known pedigree records of these inbred lines. The results indicate that SSR analysis is effective for the assessment of genetic diversity among maize inbred lines and for the assignment of inbred lines to heterotic groups.     

Wild mouse open field behavior is embedded within the multidimensional data space spanned by laboratory inbred strains

The vast majority of studies on mouse behavior are performed on laboratory mouse strains (Mus laboratorius), while studies of wild-mouse behavior are relatively rare. An interesting question is the relationship between the phenotypes of M. laboratorius and the phenotypes of their wild ancestors. It is commonly believed, often in the absence of hard evidence, that the behavior of wild mice exceeds by far, in terms of repertoire richness, magnitude of variables and variability of behavioral measures, the behavior of the classical inbred strains. Having phenotyped the open field behavior (OF) of eight of the commonly used laboratory inbred strains, two wild-derived strains and a group of first-generation-in-captivity local wild mice (Mus musculus domesticus), we show that contrary to common belief, wild-mouse OF behavior is moderate, both in terms of end-point values and in terms of their variability, being embedded within the multidimensional data space spanned by laboratory inbred strains. The implication could be that whereas natural selection favors moderate locomotor behavior in wild mice, the inbreeding process tends to generate in mice, in some of the features, extreme and more variable behavior.     

Plant nucleases. IV. Genetic control of ribonuclease activity in corn endosperm

Ribonuclease activity in the endosperms of 14 corn (Zea mays L.) inbreds ranged from 285 to 1305 units/g fresh weight 50 days after pollination. Activity is low in the inbred M14 and high in the inbred WF9. Hybrid endosperms contain intermediate levels of ribonuclease, and segregation occurs in the F₂ generation. The ribonuclease contents of the opaque-2 versions of nine inbred lines ranged from 1288 to 5110 units/g. The floury-2 mutation apparently does not affect ribonuclease content. Two or more genes may be involved in the control of ribonuclease content of developing endosperms.Cooperative investigations of the Plant Science Research Division, Agricultural Research Service, U.S. Department of Agriculture, and the Illinois Agricultural Experiment Station, Urbana, Illinois.     

Identification of candidate markers associated with agronomic traits in rice using discriminant analysis

Plant genetic mapping strategies routinely utilize marker genotype frequencies obtained from progeny of controlled crosses to declare presence of a quantitative trait locus (QTL) on previously constructed linkage maps. We have evaluated the potential of discriminant analysis (DA), a multivariate statistical procedure, to detect candidate markers associated with agronomic traits among inbred lines of rice (Oryza sativa L.). A total of 218 lines originating from the US and Asia were planted in field plots near Alvin, Texas, in 1996 and 1997. Agronomic data were collected for 12 economically important traits, and DNA profiles of each inbred line were produced using 60 SSR and 114 RFLP markers. Model-based methods revealed population structure among the lines. Marker alleles associated with all traits were identified by DA at high levels of correct percent classification within subpopulations and across all lines. Associated marker alleles pointed to the same and different regions on the rice genetic map when compared to previous QTL mapping experiments. Results from this study suggest that candidate markers associated with agronomic traits can be readily detected among inbred lines of rice using DA combined with other methods described in this report.N. Zhang and Y. Xu contributed equally to work and considered as first authors.Approved for publication by the Director of the Louisiana Agricultural Experiment Station as paper no. 04-14-0335.     

Application of simple sequence repeat (SSR) markers for molecular diversity and heterozygosity analysis in maize inbred lines

There is an important role of understanding the genetic diversity among and within inbred lines at the molecular level for maize improvement in different breeding programs. The present study was devoted to estimate the level of genetic diversity among the inbred lines of maize using the simple sequence repeat analysis (SSR). The application of six different SSR markers successfully provided the information on similarity or diversity as well as the heterozygosity of the allelic loci for all the eight inbred line of maize.