Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 8

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
1

Variability of minor tooth traits and allozymic diversity in brown hare Lepus europaeus populations

100%
Suchentrunk F.
Acta Theriologica. Supplement
|
1993
|
tom 38
|
nr 2
Two contrasting hypotheses on the relationship between dental character variability and biochemical-genetic diversity: (1) "influence of developmental homeostasis" and (2) "genetic-phenetic variation correlation" were tested in brown hare Lepus europaeus Pallas, 1778 populations. Interindividual variability (IV) and fluctuating asymmetry (FA) of 12 non-metrical characters of third lower premolars (P3) as well as allozymic heterozygosity (H) at 13 polymorphic loci was examined in 385 individuals from 19 geographical sampling units (GSU) in Austria. Juveniles and adults were discriminated according to dry eye lens weights. Sex was determined from internal reproductive organs. IV was calculated as the mean standard deviation of the 11 tooth characters in each GSU. GSU-specific FA was calculated as the mean FA of individuals (FAin), where FAin was the percentage of characters found asymmetric in individuals of a GSU. While IV did not show any significant relationship with H at the population level, FA of adults was significantly positively correlated (rs = +0.650, p < 0.05) with H. In juveniles a trend (rs = +0.399, ns) for such a correlation was apparent too. This finding corresponds to the "genetic-phenetic variation correlation hypothesis". Variability of both character systems is high in populations with high genomic variability, because both character systems concordantly portray gene pool diversity. Both IV and FA was significantly lower in juveniles than in adults. Since no ontogenic changes in P3 characters were found, this age-specific difference appears to result from selection against juveniles with low P3 variability (i.e. low genomic diversity). However, H was not lower in juveniles as compared to adults.
2

Identical cheek tooth anomalies in two Polish brown hare populations

63%
Suchentrunk F., Markowski J.
Acta Theriologica
|
1992
|
tom 37
|
nr 4
Mandibles of 258 brown hares Lepus europaeus Pallas, 1778 from Poland were controlled for abnormal expression of the premolars. In four individuals a reciprocal transposition of the right and left third lower premolars was found. In addition, all the affected premolars were rotated. The rotation showed bilateral symmetry in each of the four specimens. A genetical basis is suggested for this type of tooth anomaly.
3

Effects of stock and rearing conditions on night-roosting in Pheasants Phasianus colchicus L.

51%
Bartels A., Suchentrunk F., Vodnansky M.
Acta Ornithologica
|
1993
|
tom 28
|
nr 2
69-74
The tendency to roost overnight was studied in 91 juvenile "black-necked" and "ring-necked" Pheasants reared either under "semi-natural" or "commercial" pheasantry conditions. The birds were kept in cages in 4 different groups. Observations were carried out in 50 evenings. Numbers of individuals roosted per group were determined usually at four counts per evening in intervals of 10min., with the last count immediately before darkness. Data on weather parameters were recorded in each evening. All statistical tests were performed using arc-sine-transformed proportion values of roosted birds. The Pheasants started night-roosting at an age of 40-50 days. Roosting activity began approx. 40 min. before darkness and locomotory activity ceased right before darkness. Among the 4 rearing-groups considered, the tendency towards night-roosting was highest (median = 63.5%) in "black-necks" reared under "semi-natural" conditions and lowest (median = 35.0%) in "ring-necks" reared under commercial pheasantry conditions. Rainfall lowered the tendency from a median of 43% to 35%.
4

Developmental stability and canalization of limb bones of brown hares Lepus europaeus with varying levels of heterozygosity

51%
Sert H., Suchentrunk F., Ludescher B., Hacklander K.
Acta Theriologica
|
2005
|
tom 50
|
nr 2
We have studied fluctuating asymmetry (FA), as indicator of developmental stability, and between-individual variation, as surrogate of developmental canalization (DC), in long bones (humerus, ulna, radius, femur, tibia) of 72 wild-living adult-sized brown haresLepus europaeus Pallas, 1778 with variable individual heterozygosity (H).H was calculated from 13 polymorphic allozyme loci. According to the “over-dominance hypothesis”, we expected increased developmental stability and canalization at higherH-levels. But at the individual level we did not find any significant correlation between overall FA (FAI) andH. Also, standard deviations (SD) of mean length (over both body sides) of bones did not differ between individuals from two intentionally created groups of hares, namely one with high and one with lowH. FA-indices and variances of FA-indices of bone lengths did not differ significantly when compared between two intentionally created groups of hares with high and low SD of bone lengths, respectively. These latter findings suggest that developmental stability and DC are two separate or partly separate mechanisms of developmental homeostasis in the studied appendicular skeleton, and thatH has no traceable effect on develop-mental homeostasis. If there is still such an effect, it should be clearly smaller than a possibly combined effect of (presently uncontrolled) environmental stressors.
5

An integrative analysis of genetic differentiation in the brown hare Lepus europaeus based on morphology, allozymes, and mitochondrial DNA

51%
Hartl G. B., Suchentrunk F., Nadlinger K., Willing R.
Acta Theriologica. Supplement
|
1993
|
tom 38
|
nr 2
A total of 469 brown hares Lepus europaeus Pallas, 1778 from 20 sampling sites in Austria were examined for genetic diversity within and among populations by means of horizontal starch gel electrophoresis. Fourteen out of 54 presumptive structural loci were polymorphic, one of which was excluded from further population genetic analyses due to the occurrence of a null-allele. The mean proportion of polymorphic loci (P) was 15.3% (SD 2.2%), and mean expected average heterozygosity (He) was 4.6% (SD 0.5%). Both relative (Fst = 5.4%) and absolute (mean Nei's 1978 D = 0.0016, SD 0.0016) genetic differentiation among populations were low, suggesting a generally high level of migration. Cluster analysis revealed some separation of brown hare populations in western and northern Austria from those in the east and in the south. In 131 individuals, mtDNA was digested with a battery of 16 restriction endonucleases. Besides the standard type I which occurred exclusively in most of the populations, five additional haplotypes, each of them deviating from type I by one base pair substitution, were detected. Together with rare alleles at allozyme loci, the distribution of variant haplotypes corroborated the spatial pattern obtained by allozyme distances and suggested considerable immigration of brown hares from the adjacent countries in the east and south. Twenty non-metric skull traits were scored in 443 individuals. Character variants were dichotomized (0/1) and the respective frequencies were used to calculate C. A. B. Smith's 'mean measure of divergence' (MMD) among five population groups. Morphological differentiation was in accordance with the major population genetic pattern as revealed by molecular techniques. MtDNA variation (nucleon diversity, nucleotide diversity) and morphological variation (mean of SD in single characters) within populations were not significantly associated with one another, and did not show a relationship with indices of genetic variation obtained by allozyme analysis. These findings suggest that variability in only one of these characters cannot be considered representative for overall gene pool diversity within populations.
6

Dental and cranial anomalies in Austrian and Polish brown hare Lepus europaeus populations

51%
Suchentrunk F., Markowski J., Janiszewski T., Hartl G. B.
Acta Theriologica
|
1992
|
tom 37
|
nr 3
A total of 598 Austrian and 1117 Polish skulls of brown haros Lepus europaeus Pallas, 1778 was examined for dental anomalies, occurrence of Wormian bones and formation of a fenestra in the fossa mandibulars assis temporalis. In addition, the degree of ossification of skull sutures and frequencies oi traceable interparietal sutures were analysed in Austrian hares. Frequencies of missing M3 were 1.95% for Austrian and 2.1% for Polish hares from 1986 - 1990. No significant differences as to age or sex were found for incidences of missing M'1; the left side of the tooth row was significantly more often affected by missing M'\ which indicates directional asym­metry. Rotation of the I2 (mainly of low magnitude) was noticed in 27.9% of subadult and adult Austrian hares. Occurrences of all other dental anomalies such as abnormal shape of M', missing I2, missing M3, supernumerary I2, additional upper molar and various cases of malformation or irregular position of teeth were very low, respectively. Ossification of skull sutures was presently rcduced as compared to the material in­vestigated by Cabofi-Raczyftska (1964) and regional differences in the degree of suturai obliteration were found. Temporal fenestration was encountered in 24.6% of subadult and adulL Austrian hares and in 11.6% in Polish hares sampled during 1986 - 1990 (p < 0.001). Frequency of temporal fenestration increased with age: 2.9% in fetuses/ neonates, 16.5% in subadult and 28.1% in adult hares from Austria (p < 0.01, d.f. = 2); 8.7% in subadult and 23.8% in adult Polish specimens. Average frequency of Wormian bones in Austrian hares was 4.8% and 4.4% in the Polish material. Within subadults 3.7% of males and 16.3% of females (p < 0.01) exhibited a traceable outline of the os interparietale.
7

Allozyme evolution and the molecular clock in the Lagomorpha

51%
Grillitsch M., Hartl G. B., Suchentrunk F., Willing R.
Acta Theriologica
|
1992
|
tom 37
|
nr 1-2
In order to provide a scale of genetic distances in the Lagomorpha, biochemical- systematic relationships among Lepus europaeus, Lepus timidus, Oryctolagus cuniculus (Leporidae) and Ochotona rufescens (Ochotonidae) were examined by hori­zontal starch gel electrophoresis of 38 isozyme systems. Nei's (1978) genetic distances were calculated over 58 presumptive structural loci and used for the construction of numerical dendrograms. The stability of clusters was examined by the jackknife method and by comparison to a Hennigian cladogram. All these procedures revealed a constant picture of lagomorph relationships, which is in accordance with the conclusions drawn from other evidence. Divergence times were estimated using two fundamentally different approaches. They were in good agreement with paleontological data (0.49myr between the Lepus species, 3.65myr between Lepus and Oryctolagus, 37.5myr between Leporidae and Ochotonidae), but only when calculated in different ways at low and at high taxonomic levels. The results suggest a temporal acceleration of the rate of allozyme evolution in the Leporidae due to rapid adaptive radiation of biochemically highly polymorphic taxa.
8

Population genetics of Bulgarian brown hares Lepus europaeus: allozymic diversity at zoogeographical crossroads

51%
Suchentrunk F., Michailov C., Markov G., Haiden A.
Acta Theriologica
|
2000
|
tom 45
|
nr 1
Allozymic variability of 157 brown hares Lepus europaeus (Pallas, 1778) from eight sampling localities in Bulgaria was studied by horizontal starch gel electrophoresis of 50 putative structural gene loci. The present data were compared to an adjusted data set of brown hares from central Europe (Austria), published earlier, in order to test the hypothesis of increased genetic diversity in brown hares from the southeastern European zoogeographical crossroads region, a possible refuge for brown hares during the last glaciation period. No new polymorphic locus was detected, and only one new allele occurred at a low frequency in the Bulgarian hares. Nevertheless, two estimators of genetic diversity (average expected heterozygosity, Shannon-Weaver information index) where slightly higher in Bulgarian hares than in central European hares. In contrast, some alleles found earlier in various parts of central Europe did not occur in the Bulgarian samples. The latter finding suggests that gene pools of central European brown hares might have received gene flow from other parts of Europe during their postglacial (re-(colonization process. This accords to an alternative hypothesis of postglacial colonization of central Europe from both southeastern and southwestern refuges.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.