Linkage analyses among five esterase loci in the laboratory rat (Rattus norvegicus)

A cluster of esterase loci has been identified on a segment of a rat linkage group V; however, the linear order of all the loci has not been established. We estimated the recombination frequencies of two locus combinations among five esterase loci (Es-1, Es-2, Es-3, Es-4, and Es-Si) and the linear order of the loci by using three sets of backcross matings: (1) (K:W × IS) × IS, (2) (K:W × IS) × IS, and (3) (SHR × W) × W). The linear order was determined to be Es-1-Es-4-Es-2-Es-3-Es-Si, although the order of Es-2 and Es-4 remains tentative. The sexinfluenced esterase (Es-Si) was demonstrated to be distinct from Es-1 and was proposed to be Es-Si locus with two alleles of Es-Si ^a (positive) and Es-Si ^b (null).This work was partly supported by Grants-in-Aid for Scientific Research, No. 339020 (1978), from the Ministry of Education, Science and Culture, Japan.     

Evidence for linkage between four esterase loci in the rat (Rattus norvegicus)

Two new esterase polymorphisms have been described in tissue homogenates of the four rat strains August/Orl, LEW/Orl, Long Evans/Orl, and WAG/Orl. Independent expression of these polymorphisms in the different strains and in various tissues of a particular animal agrees with the separate genetic control hypothesis; the gene symbols Es-4 and Es-5 have been assigned to the loci. Transmission of both genes follows a normal autosomal recessive Mendelian pattern; preliminary data indicate tight linkage between these loci and the previously described Es-2 and Es-3 loci.     

Polymorphic microsatellite loci in peafowl (Pavo cristatus)

Understanding how the genetic characteristics of parents influence reproductive output is central to predicting the dynamics of small, endangered populations. We conducted a breeding experiment to look at the paternal genetic effects on offspring sex, fertility and growth in the peafowl (Pavo cristatus). Microsatellite loci were developed to allow maternity assignment and thus to allow us to separate maternal from paternal effects. We found 19 polymorphic loci in our inbred, captive population, six of which were only slightly polymorphic (H_E range: 0.04–0.70). The remaining 13 loci were polymorphic enough to determine maternity by exclusion in approximately 85% of offspring.     

Polymorphic chloroplast microsatellite loci in Nelumbo (Nelumbonaceae)

? Premise of the study: To study population genetics, phylogeography, and hybridization of Nelumbo (Nelumbonaceae), chloroplast microsatellite markers were developed. ? Methods and Results: Seventeen microsatellite loci were identified from the chloroplast genomes of N. nucifera and N. lutea. Polymorphisms were assessed in three populations of N. nucifera and one population of N. lutea. Nine loci were found to be polymorphic in N. nucifera, and all 17 loci were found to be polymorphic in N. lutea. In N. nucifera, the number of alleles per locus ranged from two to six, and the unbiased haploid diversity per locus ranged from 0.198 to 0.790. In N. lutea, the number of alleles ranged from two to four, and the unbiased haploid diversity per locus ranged from 0.245 to 0.694. ? Conclusions: The identified chloroplast simple sequence repeat markers will be useful for the study of genetic diversity, phylogeography, and identification of Nelumbo cultivars.     

Skull growth in the albino rat (Rattus norvegicus)

A longitudinal study of growth in the rat skull, based on serial radiographs, has shown that by the age of one month after birth, the braincase attains some 93% of its adult (fifth-month) size whilst the facial skeleton and mandible attain but 75% of their adult size. By the third month, growth in the braincase has virtually ceased, whereas significant facial growth continues until the age of five months.     

Idiopathic megaesophagus in a rat (Rattus norvegicus)

Necropsy and histopathologic examination of a rat (Rattus norvegicus) revealed megaesophagus and gangrenous bronchopneumonia. The esophageal dilitation, mural atrophy with persistence of neural structures, regurgitation and bronchopneumonia seen in this case were similar to findings in other animals with megaesophagus.     

The major histocompatibility complex of the rat (Rattus norvegicus)

This review of the RT1 complex, the major histocompatibility complex (MHC) of the rat, focuses on genetic, genomic, evolutionary, and functional aspects at the molecular level. The class I, class II, and framework genes are listed. The physical map of the RT1 complex as revealed by analysis of clonal contigs is compared with the human and mouse MHC, and the degree of orthologous relationship is outlined. Elucidation of the RT1 complex provides important information for using the rat as a model of experimental transplantation and complex diseases.     

Polymorphic microsatellite loci in pheasant coucal (Centropus phasianinus)

Little is known about the effect of male parental care and behavioural sex‐role reversal on the mating system of birds because genetic markers for species with these characteristics are lacking. We developed primers for nine polymorphic microsatellite loci in pheasant coucals (Centropus phasianinus). Eight of the primers were also polymorphic in African black coucals (Centropus grillii). Pheasant coucals are of particular interest in the study of evolutionary and behavioural ecology, because their sex‐role reversal and extensive male parental care suggests low levels of extra‐pair fertilizations, yet they have large testes indicating sperm competition.     

Polymorphic microsatellite loci for the Japanese anchovy Engraulis japonicus (Engraulidae)

We isolated and characterized 14 polymorphic microsatellite loci in the Japanese anchovy (Engraulis japonicus) using a (GT)(13)-enriched genomic library. The numbers of alleles per locus ranged from 6 to 31, with a mean of 17.8. The observed and expected heterozygosities ranged from 0.180 to 0.949 and from 0.172 to 0.966, with means of 0.731 and 0.825, respectively. All 14 loci were in Hardy-Weinberg equilibrium and no significant linkage disequilibrium between loci pairs was detected. These microsatellite markers will be useful for analyzing the population genetic structure and gene flow of E. japonicus.     

Polymorphic microsatellite loci for eusocial wasps (Hymenoptera: Vespidae)

Hymenopterans are an important model for studying the evolution of cooperation in animal societies. Here, we characterize 19 microsatellite loci, isolated from the common wasp Vespula vulgaris, that can be used to study genetic variation in three genera (seven species) within the Vespidae. The number of alleles in V. vulgaris was moderate, varying from 2 to 14, with expected heterozygosity ranging between 0.04 and 0.93. Eleven loci amplified DNA in V. austriaca and Dolichovespula sylvestris, nine in V. germanica, eight in Vespa crabro and V. rufa, seven in D. media and only five loci could be used for D. norwegica.     

Polymorphic microsatellite loci for Japanese Spanish mackerel (Scomberomorus niphonius)

We isolated and characterized 21 polymorphic microsatellite loci in Japanese Spanish mackerel (Scomberomorus niphonius) using a (GT)(13)-enriched genomic library. Forty individuals were collected from Qingdao, China. We found 3 to 24 alleles per locus, with a mean of 8.8. The observed and expected heterozygosities ranged from 0.263 to 0.975 and from 0.385 to 0.946, with means of 0.655 and 0.685, respectively. Deviation from Hardy-Weinberg proportions was detected at three loci. Two loci showed evidence for null alleles. These microsatellite markers will be useful for population genetic analysis of Japanese Spanish mackerel.     

Polymorphic microsatellite loci in Linum usitatissimum

We report the characterization of 28 polymorphic microsatellite markers in Linum usitatissimum that allow distinguishing almost all cultivars of both flax and linseed. Polymorphism was low, ranging from two to 10 alleles per locus in the 93 cultivars screened. Linkage disequilibrium was found at about a third of the pairs of loci likely due to self‐fertilization and strong selection by breeders. We tested these loci for cross‐amplification in nine additional species of Linum and found that three species amplified a majority of loci.     

Polymorphic tetranucleotide microsatellite loci in the Hwamei (Garrulax canorus canorus) (Timaliidae)

Eight polymorphic tetrarepeat (GATA)_n, microsatellite loci were isolated from a babbler, Hwamei (Garrulax canorus canorus). We evaluated the polymorphism of these microsatellite loci by genotyping 36–48 individuals from the Asian mainland. The number of alleles for each locus ranged from eight to 29. The heterozygosity was between 0.587 and 0.978. Except for one locus, genotype frequencies of these microsatellites did not significantly deviate from the Hardy–Weinberg expectation. These markers should be useful for monitoring potential hybridization between different Hwamei subspecies and provide new insights into the mating system and geographical differentiation of these birds.     

Biochemical genetics of methylglyoxal dehydrogenases in the laboratory rat (Rattus norvegicus)

A genetic locus controlling the electrophoretic mobility of a methylglyoxal dehydrogenase (EC 1.2.1.23) in the rat is described. The locus, designatedMgd1, is expressed in liver and kidney. Inbred rat strains have fixed either alleleMgd1 ^a or alleleMgd1 ^b . Codominant expression is observed in heterozygotes, providing evidence for a tetrameric enzyme structure. Backcross progenies showed the expected 1:1 segregation ratio, and there is evidence thatMgd1 is linked toPep3 andFh1 on chromosome 13. There is also evidence for two additional methylglyoxal dehydrogenases:Mgd2, present in liver and kidney, andMgd3, present only in heart.Supported by the Deutsche Forschungsgemeinschaft (Grant Be 352/18-1).     

Polymorphic microsatellite loci in Plantago lanceolata

The genus Plantago is particularly interesting for evolutionary studies because of its wide range of mating systems. We have developed primers for five highly polymorphic microsatellite loci isolated from P. lanceolata. All five loci amplified and were polymorphic in the two populations examined, Lowsteads Beach in the United Kingdom and Duke in the United States. These new markers will allow a comparison of population structure between the outcrossing species P. lanceolata, and the highly selfing species P. major.     

Electron microscopy and microcalorimetry of the postnatal rat heart (Rattus norvegicus)

The interplay of ultrastructure and tissue metabolism was examined in neonatal, infant and adult rat hearts by electron microscopy and microcalorimetry. Morphometry was used to determine parameters of oxygen diffusion capacity (distance between capillaries and mitochondria, capillary surface density) and oxidative metabolic capacity (mitochondrial volume fraction). Thin slices and large samples of living tissue were examined calorimetrically to quantify aerobic metabolism and ischemia tolerance, respectively. After birth, rat hearts grow in parallel to body mass and show characteristics of cellular hypertrophy. Capillary surface density increases from neonatal to infant rats, and decreases to an intermediate value in adult rats. The distance between capillaries and mitochondria shows no significant changes throughout postnatal development. Mitochondrial volume fraction increases continuously until adulthood. The specific aerobic tissue metabolic rate is higher in the neonatal than in the infant and adult rat. However, the ischemic decline in metabolic rate is much slower in the neonatal rat, reflecting an elevated hypoxia tolerance. In conclusion, the neonatal rat heart exhibits a high metabolic rate despite a low mitochondrial volume fraction. The subsequent structural rearrangements can be interpreted as long-term adaptations to the increased postnatal workload and may contribute to the progressive loss of hypoxia tolerance.