Patterns of allozyme variation in tamarack (Larix laricina) from northern Ontario

1991 ◽  
Vol 69 (11) ◽  
pp. 2468-2474 ◽  
Author(s):  
Zhaowei Liu ◽  
Peggy Knowles
Keyword(s):  
Function Analysis ◽  
Geographic Location ◽  
Allozyme Variation ◽  
Wide Distribution ◽  
Genetic Distances ◽  
Larix Laricina ◽  
Northern Ontario ◽  
Total Genetic Diversity ◽  
Population Genetic Variation ◽  
Genotypic Structure

Rooted cuttings from approximately 26 trees (range 9–37) from each of 44 populations of tamarack (Larix laricina (Du Roi) K. Koch) in northern Ontario were analyzed electrophoretically for allozyme variation in 13 enzyme systems coded by 18 loci. A low level of variability relative to many other conifers was found, with expected and observed heterozygosity per population of 0.104 and 0.096, respectively, χ2 tests for allelic homogeneity among populations indicated heterogeneity (α = 0.05) at four loci. Approximately 2% of the total genetic diversity occurred among populations, with the remainder (98%) residing within populations. The mean genetic distance over all pairs of tamarack populations was 0.0025. Four methods of cluster analysis based on genetic distances and a discriminant function analysis of the genotypic structure of the populations revealed no consistent patterns of variation relative to geographic location, although one of the clustering procedures showed a weak east–west pattern. The results indicate that (i) the level of variation in these populations of tamarack is substantially less than that previously reported for its range-wide distribution; (ii) the population structure of tamarack is consistent with that of other conifers, indicating little deviation from Hardy–Weinberg expected genotypic frequencies and low levels of differentiation; and (iii) the distribution of the variation provides little evidence to support the model of two routes of tamarack post glacial reinvasion meeting west of Lake Superior. Key words: tamarack, eastern larch, Larix laricina, allozyme, isozyme, population, genetic variation, northern Ontario.

Allozyme variation in sugar maple at the northern limit of its range in Ontario, Canada

1989 ◽  
Vol 19 (4) ◽  
pp. 509-514 ◽  
Author(s):  
D. J. Perry ◽  
P. Knowles
Keyword(s):  
Genetic Variation ◽  
Sugar Maple ◽  
Geographic Distance ◽  
Allozyme Variation ◽  
Genetic Distances ◽  
Canonical Discriminant Analysis ◽  
Ancestral Population ◽  
Allelic Heterogeneity ◽  
Northern Limit ◽  
Northern Ontario

Genetic variation in five populations of sugar maple (Acersaccharum Marsh.) from northern Ontario was analysed electrophoretically for seven enzymes encoded by 11 structural loci. On average, populations were polymorphic at 38.2% of the loci, with 1.95 alleles per locus. Although FST estimates indicated that only 3% of the genetic variability was among populations, there was significant allelic heterogeneity at all polymorphic loci. Canonical discriminant analysis also indicated substantial differentiation among populations. Genetic distances between populations ranged from 0.0009 to 0.0125, but no relationship with geographic distance was apparent. It is suggested that pockets of sugar maple found at the northern limit of its range in Ontario may be relics of a more continuous ancestral population which may have existed during the hypsithermal interval.

Cholecystokinin receptors

1995 ◽  
Vol 269 (5) ◽  
pp. G628-G646 ◽  
Author(s):  
S. A. Wank
Keyword(s):  
Function Analysis ◽  
Receptor Gene ◽  
Wide Distribution ◽  
Receptor Expression ◽  
Receptor Subtypes ◽  
Cck Receptors ◽  
High Affinity ◽  
Recombinant Receptor ◽  
Receptor Pharmacology ◽  
Specific Variation

The cholecystokinin (CCK) and gastrin families of peptides act as hormones and neuropeptides on central and peripheral CCK receptors to mediate secretion and motility in the gastrointestinal (GI) tract in the physiological response to a normal meal. CCK and its receptors are also widely distributed in the central nervous system (CNS) and contribute to the regulation of satiety, anxiety, analgesia, and dopamine-mediated behavior. Although the wide distribution, myriad number of functions, and reported pharmacological heterogeneity of CCK receptors would suggest a large number of receptor subtypes, the application of modern molecular biological techniques has identified two CCK receptors, CCK-A receptor (CCK-AR) and CCK-B receptor (CCK-BR), that mediate the actions of CCK and gastrin; gastrin receptors have been found to be identical to CCK-BR. CCK-AR, found predominantly in the GI system and select areas of the CNS, have high affinity for CCK and the nonpeptide antagonist L-364,718, whereas CCK-BR, found predominantly in the CNS and select areas of the GI system, have high affinity for CCK and gastrin and the nonpeptide antagonist L-365,260. Both CCK-AR and CCK-BR are highly conserved between species, although there is some tissue-specific variation in expression. Recombinant receptor expression faithfully reproduces the native receptor pharmacology and signal transduction pathways, allowing direct comparisons of receptor function between species as well as serving as a convenient source of receptor. Our present knowledge of the chromosomal localization, receptor gene structure, and primary sequence will allow further studies in disease association, receptor regulation, and structure-function analysis.

scholarly journals Divergência genética entre acessos de mentrasto do Estado do Tocantins através de marcadores RAPD

2013 ◽  
Vol 4 (4) ◽  
pp. 290-298
Author(s):  
Elainy Martins Oliveira ◽  
Waldesse Oliveira Junior ◽  
Jaqueline Oliveira ◽  
Henrique Guilhon De Castro
Keyword(s):  
Genetic Diversity ◽  
Rapd Markers ◽  
Geographic Location ◽  
Genetic Distances ◽  
Similarity Coefficients ◽  
Ageratum Conyzoides ◽  
Genetic Studies ◽  
Low Degree ◽  
Medicinal Properties ◽  
Degree Of Association

Ageratum conyzoides (Asteraceae) is known in Brazil for its medicinal properties being mainly used as painkiller and anti-inflammatory. Due to the existence of few genetic studies for this species, this work aimed to characterize the genetic diversity among nine accessions from different sites at Tocantins state, to provide information about its genetic resources. Similarity coefficients obtained varied from 48% to 80%, result of amplification of 102 fragments, of which 72 (70.5%) were polymorphic. Groupment analysis allowed the differentiation in three groups. One of them was distinguished because it presented the highest similarity among all, being composed by ANA and NAT (80% similarity). In general, these data showed there is low degree of association between the geographic location of the accessions and the genetic distances. So, the collected accession ns in Tocantins state presented considerable genetic variability and the efficiency of RAPD markers for such characterization was here proven.

Allozyme, chromosomal and morphological variability in the Litoria lesueuri species group (Anura : Hylidae), including a description of a new species

2004 ◽  
Vol 52 (1) ◽  
pp. 1 ◽  
Author(s):  
S. C. Donnellan ◽  
M. J. Mahony
Keyword(s):  
Discriminant Function ◽  
Discriminant Function Analysis ◽  
Function Analysis ◽  
Morphological Variability ◽  
Allozyme Variation ◽  
Species Group ◽  
Separate Species ◽  
Morphometric Variation ◽  
Genetic Groups ◽  
Eastern Australia

Allozyme variation at 36 loci was screened in 179 individuals of the Litoria lesueuri species group from 33 locations from across the species' range in eastern Australia. We identified three genetic groups, with discrete and disjunct distributions, that we consider to be separate species. The northernmost group, L.�jungguy, sp. nov., had a distinctive standard and C-band karyotype, while the karyotypes of the two southern groups, L. lesueuri (Duméril & Bibron, 1841) and L. wilcoxii Gunther, 1864, differed only in minor details of their C-band patterns. Stepwise discriminant function analysis of morphometric variation among 13 meristic variables was able to discriminate L. lesueuri and L. wilcoxii in 100% of cases but discrimination between L. wilcoxii and L. jungguy was less successful, with 75% and 56% of each group respectively being correctly classified. Locations with inter-group hybrids were identified in the Australian Capital Territory, mid-east Queensland and two localities in far north Queensland. However, each of the groups has a large geographic range within which there was relative allozyme and karyotype uniformity. On the basis of the genetic data, each group is herein elevated to species status. Existing types were assigned to their respective genetic groups on the basis of a discriminant function analysis. Formal taxonomic accounts are provided. The closely related L. booroolongensis (Moore, 1961), sole member of the L.�booroolongensis species group, differed allozymically from all three species of the L. lesueuri species group but only from the northern species in its karyotype. Small genetic distances between L.�booroolongensis and members of the L. lesueuri species group indicate a close relationship for the two species groups.

Two new species of lizards from the Liolaemus lineomaculatus section (Squamata: Iguania: Liolaemidae) from southern Patagonia

Zootaxa ◽  
2011 ◽  
Vol 3120 (1) ◽  
pp. 1 ◽  
Author(s):  
MARIA FLORENCIA BREITMAN ◽  
MICAELA PARRA ◽  
CRISTIAN HERNÁN FULVIO PÉREZ ◽  
JACK WALTER SITES, JR.
Keyword(s):  
New Species ◽  
Analysis Of Variance ◽  
Genetic Characterization ◽  
Function Analysis ◽  
Univariate Analysis ◽  
Principal Component ◽  
Genetic Distances ◽  
Southern Patagonia ◽  
Two New Species ◽  
Genetic Characters

Two new species of the lineomaculatus clade of the Liolaemus lineomaculatus section are described from southern Patagonia in Argentina. Liolaemus morandae sp. nov. is found in S Chubut province and Liolaemus avilae sp. nov. inhabits NW Santa Cruz province. Several tests were performed to diagnose these new species as distinct lineages. Univariate analysis of variance (ANOVA), principal component analysis (PCA), discriminant function analysis (DFA), non-parametric multivariate analysis of variance (NPMANOVA), as well as a genetic characterization through molecular analysis of variance (AMOVA) were performed; genetic distances between described and these new species are reported. The new Liolaemus species differ from other members of the lineomaculatus group in morphometric, meristic, qualitative and genetic characters; moreover they inhabit different phytogeographical provinces and districts. With these descriptions, the number of species now recognized in the lineomaculatus section is twenty one (including one more description that is in press).

scholarly journals Characterization of Mexican Isolates of Colletotrichum lindemuthianum by Using Differential Cultivars and Molecular Markers

1998 ◽  
Vol 88 (4) ◽  
pp. 292-299 ◽  
Author(s):  
Mario González ◽  
Raul Rodríguez ◽  
Maria Elena Zavala ◽  
Juan L. Jacobo ◽  
Fernando Hernández ◽  
...  
Keyword(s):  
Molecular Markers ◽  
Random Amplified Polymorphic Dna ◽  
Geographic Location ◽  
Genetic Distances ◽  
Colletotrichum Lindemuthianum ◽  
Aflp Data ◽  
Bootstrap Analysis ◽  
Differential Cultivars ◽  
Bean Anthracnose

Differential cultivars and molecular markers were used to analyze 59 isolates of the bean anthracnose pathogen, Colletotrichum lindemuthianum, from different regions of Mexico. Ten distinct races were determined, three of which had not been reported previously in Mexico. Isolates were found to infect only a narrow range of the differential cultivars used and were restricted to cultivars of Middle American origin. A comparison of random amplified polymorphic DNA and amplified fragment length polymorphism (AFLP) analyses was carried out on a subset of the fungal isolates. Determination of genetic distances based on AFLP data and production of a dendrogram demonstrated two levels of association: i) isolates classified into two major groups according to the type of cultivar or system of cultivation from which they originated, and ii) isolates could be classified into smaller subgroups generally associated with the geographic location from which they were obtained. Bootstrap analysis and determination of confidence intervals showed these geographic groupings to be extremely robust.

Microgeographical Patterns of Allozyme Variation in Casuarina cunninghamiana Miq Within and Between the Murrumbidgee and Coastal Drainage Systems

1989 ◽  
Vol 37 (2) ◽  
pp. 181 ◽  
Author(s):  
NJ Moore ◽  
GF Moran
Keyword(s):  
Genetic Diversity ◽  
Large Population ◽  
Drainage System ◽  
Allozyme Variation ◽  
Distance Measures ◽  
Drainage Systems ◽  
Casuarina Cunninghamiana ◽  
Total Genetic Diversity ◽  
Geographic Clustering

Within the Murrumbidgee drainage system, 100 seedlings from each of 14 populations of Casuarina cunninghamiana were assayed for their allozyme genotypes at 14 loci. The levels of genetic variation were fairly similar in all populations. There was no geographic clustering of populations based on genetic distance measures. Only 3.8% of the total genetic diversity could be apportioned among populations within the drainage system. In six additional populations, branchlets from 50 trees per population were assayed for their allozyme genotypes at 27 loci. Three populations were from the Murrumbidgee drainage system and each of the others from a different coastal drainage. The mean expected heterozygosities for coastal and inland zones were 0.139 and 0.093 respectively. Of the total genetic diversity 10.7% could be apportioned among the four drainages. The results of this study suggest that for in situ conservtion of C. cunninghamiana within a region, more emphasis should be placed on conserving one large population from each major drainage system rather than a number of populations within one or two drainage systems.

Genetic diversity among geographically separated populations of Nepenthes mirabilis

Biologia ◽  
2006 ◽  
Vol 61 (3) ◽  
Author(s):  
Arunrat Chaveerach ◽  
Alongkod Tanomtong ◽  
Runglawan Sudmoon ◽  
Tawatchai Tanee
Keyword(s):  
Genetic Diversity ◽  
Diversity Index ◽  
Geographical Area ◽  
Inter Simple Sequence Repeat ◽  
Genetic Distances ◽  
High Genetic Diversity ◽  
Total Genetic Diversity ◽  
Environmental Variations ◽  
Diversity Profile ◽  
Great Genetic Diversity

AbstractThe distribution of Nepenthes mirabilis ranges from Northeast (NE) to South (S) Thailand. Eleven individuals from NE, S and Suen Jatujak market in Bangkok, Central (C) Thailand, were collected and divided into four populations according to their geographical areas. These four populations were analyzed to determine a genetic diversity profile using thirteen inter-simple sequence repeat markers. The individuals produced 75.18% polymorphic banding profiles. The Shannon’s index was used to estimate genetic diversity. Total genetic diversity (H T) and inter-population genetic diversity (H S) were 0.854 and 0.678, respectively. The degree of genetic differentiation (G ST) of the species populations is 0.206, whereas the gene flow (Nm) among all the various geographical area populations is 1.016. Both the dendrogram and the results of the Shannon’s diversity index suggest great genetic diversity. These results support the broad range of distribution sites of Nepenthes mirabilis, which would require high genetic diversity to adapt to the environmental variations that can be found between NE, C, and S Thailand. ANOVA shows that the genetic diversity in each population is not significantly different (P > 0.05). Mantel tests reveal that geographical distance is an important factor for affecting the genetic distances among populations.

Allozyme variation in the Polygonum lapathifolium complex

1991 ◽  
Vol 69 (10) ◽  
pp. 2261-2270 ◽  
Author(s):  
Laurie L. Consaul ◽  
Suzanne I. Warwick ◽  
John McNeill
Keyword(s):  
North American ◽  
Taxonomic Status ◽  
Allozyme Variation ◽  
Genetic Distances ◽  
Allozyme Data ◽  
Separate Species ◽  
The North ◽  
Polygonum Lapathifolium ◽  
Polygonum Pensylvanicum ◽  
European Populations

The Polygonum lapathifolium complex consists of populations that are widely distributed in the Northern Hemisphere and that have been classified at different taxonomic levels. Allozyme data were used to test the current North American taxonomic status of members of the complex (including P. lapathifolium var. lapathifolium, P. lapathifolium var. salicifolium, and P. scabrum) and to verify diploidy in the P. lapathifolium complex and polyploid origins of the morphologically similar P. persicaria and P. pensylvanicum. Of the 15 enzyme systems surveyed in 50 populations of the complex, only 3 of the 23 loci (Acon, Lap, and Skdh) were polymorphic in the North American populations and a total of 6 loci in European populations. Fifteen multilocus genotypes were evident in the complex. Four genotypes (all with Lap-10.67 were exclusive to North American populations of P. lapathifolium, providing support for a North American element of the complex. Nine genotypes (all with Lap-10.63) were found in North American and European populations of P. scabrum, all European populations of the P. lapathifolium complex, and three populations of North American P. lapathifolium var. lapathifolium. Lap-10.67 was also found in the native tetraploid P. pensylvanicum, whereas Lap-10.63 was found in the introduced tetraploid P. persicaria. Genetic distances among populations did not support the current taxonomic divisions within the complex, nor did it support separate species status of P. scabrum. Allozyme data provided support for the allotetraploid origins of P. pensylvanicum and P. persicaria, with members of the P. lapathifolium complex as one of the parents of each. Key words: Polygonum lapathifolium, Polygonum scabrum, Polygonum pensylvanicum, Polygonum persicaria, allozymes.

Diversity of Washoe pine and comparisons with allozymes of ponderosa pine races

1990 ◽  
Vol 20 (3) ◽  
pp. 298-308 ◽  
Author(s):  
Charles R. Niebling ◽  
M. Thompson Conkle
Keyword(s):  
Genetic Distance ◽  
Great Basin ◽  
Ponderosa Pine ◽  
Rocky Mountain ◽  
Electrophoretic Analysis ◽  
Allozyme Variation ◽  
Genetic Distances ◽  
Isolated Populations ◽  
The North ◽  
The Pacific

Washoe pine (Pinuswashoensis Mason and Stockwell), a narrow endemic native to mountains on the western rim of the Great Basin in northeastern California and northwestern Nevada, may be on the verge of extinction. Lowered genetic diversity and increased interpopulation differentiation are expected evolutionary consequences for small, isolated populations like those of Washoe pine. But the species has levels of allozyme variation (estimated average heterozygosity for 26 loci equals 0.148) similar to those for widespread geographic races of ponderosa pine (Pinusponderosa Laws.), which are likely to be its closest extant relatives. Heterozygosity in ponderosa pine was 0.144 in the Pacific race, 0.178 in the North Plateau race, and 0.164 in the Rocky Mountain race. Electrophoretic analysis of trees in the three well-documented populations of Washoe pine revealed only minor and nonsignificant population to population differentiation (98.4% of allozyme variation was among samples within populations). Pair-wise genetic distances between the Washoe populations and the three northern races of ponderosa pine indicated that its closest similarity was with the North Plateau race (Nei's unbiased genetic distance averaged 0.004); the next closest similarity was with samples of the Pacific race (genetic distance 0.013). Washoe pine and the Pacific and North Plateau races of ponderosa pine were all strongly differentiated from the Rocky Mountain race of ponderosa pine (genetic distances were 0.066, 0.082, and 0.060, respectively. The few remaining populations of Washoe pine may be a potentially valuable gene source for the yellow pines of North America.

Sign in / Sign up

Export Citation Format

Share Document