Selection for Substrate Reflectance-matching in Two Populations of Red-chinned Lizards (Sceloporus undulatus erythrocheilus) from Colorado

1989 ◽  
Vol 121 (1) ◽  
pp. 197 ◽  
Author(s):  
J. E. Gillis
Keyword(s):  
Sceloporus Undulatus ◽  
Selection For ◽  
Two Populations

scholarly journals Selection for Ethanol Tolerance in Two Populations of Drosophila Melanogaster Segregating Alcohol Dehydrogenase Allozymes

1979 ◽  
Vol 32 (3) ◽  
pp. 387 ◽  
Author(s):  
John B Gibson ◽  
NigeI Lewis ◽  
MichaeI Adena ◽  
Susan R Wilson
Keyword(s):  
Drosophila Melanogaster ◽  
Alcohol Dehydrogenase ◽  
Ethanol Tolerance ◽  
Selection For ◽  
Two Populations

Selection for ethanol tolerance was equally successful in two populations of D. melanogaster in both of which the frequency of AdhF was 0�5 at the start of the experiment.

scholarly journals Germination Patterns in Seeds Produced in Apical and Basal Fruits of Two Thlaspi arvense Populations

Agronomy ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 756
Author(s):  
Eva Edo-Tena ◽  
Russ W. Gesch ◽  
Aritz Royo-Esnal
Keyword(s):  
Germination Percentage ◽  
Temperate Climate ◽  
Oilseed Crop ◽  
Seed Selection ◽  
Thlaspi Arvense ◽  
Production Site ◽  
Field Pennycress ◽  
Selection For ◽  
The One ◽  
Two Populations

The aim of the present work is to study possible differences in the germination behavior of apical and basal seeds (produced in the upper and lower fruits of the infruitescence), of two populations of field pennycress (Thlaspi arvense), both produced in a Mediterranean and a continental temperate climate. The results showed that among the three studied factors (population, seed type, production site), only the production site was relevant for the total germination, germinating those produced in Morris in a greater amount than those produced in Lleida. Germination models could be applied only to seeds produced at Morris (>10% germination), and despite the lack of differences in the total germination percentage, germination rates (speed—b parameter—and time to 50% germination—G50) differed between population and seed types—apical seeds from the Spanish population germinated faster (lower b parameter) than the rest, while apical seeds of both populations germinated faster than the corresponding basal seeds (lower G50). The results show, on the one hand, the importance of the seed production site if this species was considered as a commercial oilseed crop and, on the other hand, differences that will help seed selection for seed germination and establishment improvement of pennycress.

EFFECTS OF SELECTION FOR SPEED OF GERMINATION ON ESTABLISHMENT, VIGOR, AND YIELD IN ALTAI WILD RYEGRASS

1977 ◽  
Vol 57 (4) ◽  
pp. 1085-1090 ◽  
Author(s):  
T. LAWRENCE
Keyword(s):  
Field Test ◽  
Seed Yield ◽  
Dry Matter ◽  
Germination Index ◽  
Dry Matter Yield ◽  
Stand Establishment ◽  
Greenhouse Test ◽  
Selection For ◽  
Two Populations

Selection for fast and slow germination in Altai wild ryegrass (Elymus angustus Trin.) through three cycles of selection resulted in significant differences in the speed of germination index between the two populations. The fast germinating population established significantly better in a field test than the slow germinating population. Significant differences, although not large, were also found between the populations for spring vigor, seed yield and dry matter yield. However, observations from a greenhouse test indicate that these differences were attributable to differences in stand establishment in the field test rather than directly attributable to selection for speed of germination. It is suggested that selection for fast germination would be useful in breeding better establishing strains of Altai wild ryegrass. This would have little effect on either spring vigor or yield of seed and forage.

scholarly journals Decanalization of scutellar bristle number in Drosophila

1971 ◽  
Vol 17 (2) ◽  
pp. 95-101 ◽  
Author(s):  
W. R. Scowcroft ◽  
B. D. H. Latter
Keyword(s):  
Marked Reduction ◽  
Test System ◽  
Developmental Stability ◽  
Base Population ◽  
Wild Type ◽  
X Ray ◽  
Bristle Number ◽  
Selection For ◽  
Two Populations

SUMMARYA major difference in developmental stability has been demonstrated between two populations produced by artificial selection for supernumerary scutellar bristles. The test system involves the substitution of an X-ray induced partial revertant of sc1 for the wild-type allele at the scute locus, enabling direct comparisons to be made of the degree of canalization at the wild-type level of expression of the character. One population is comparable with the unselected Canberra stock in stability, though it differs appreciably in mean bristle number: the other population shows a marked reduction in the level of regulation of bristle number variability. The alleles responsible for the reduced level of canalization are rare in the base population, and are of particular importance in the determination of limits to directional selection. Their effects on developmental stability have been shown to depend on the activity of the allele at the scute locus.

scholarly journals Frequent monoallelic or skewed expression for developmental genes in CNS-derived cells and evidence for balancing selection

2018 ◽  
Vol 115 (44) ◽  
pp. E10379-E10386 ◽  
Author(s):  
Sergio Branciamore ◽  
Zuzana Valo ◽  
Min Li ◽  
Jinhui Wang ◽  
Arthur D. Riggs ◽  
...  
Keyword(s):  
Balancing Selection ◽  
Developmental State ◽  
Mouse Strains ◽  
Cpg Dinucleotides ◽  
Clonal Cell Lines ◽  
Cell Type Specific ◽  
Selection For ◽  
Overlapping Classes ◽  
Two Populations ◽  
Development And Evolution

Cellular mosaicism due to monoallelic autosomal expression (MAE), with cell selection during development, is becoming increasingly recognized as prevalent in mammals, leading to interest in understanding its extent and mechanism(s). We report here use of clonal cell lines derived from the CNS of adult female F1 hybrid (C57BL/6 X JF1) mice to characterize MAE as neural stem cells (nscs) differentiate to astrocyte-like cells (asls). We found that different subsets of genes show MAE in the two populations of cells; in each case, there is strong enrichment for genes specific to the respective developmental state. Genes that exhibit MAE are 22% of nsc-specific genes and 26% of asl-specific genes. Moreover, the promoters of genes with MAE have reduced CpG dinucleotides but increased CpG differences between the two parental mouse strains. Extending the study of variability to wild populations of mice, we found evidence for balancing selection as a contributing force in evolution of those genes showing developmental specificity (i.e., expressed in either nsc or asl), not just for genes showing MAE. Furthermore, we found that genes showing skewed allelic expression (SKE) were similarly enriched among cell type-specific genes and also showed a heightened probability of balancing selection. Thus, developmental stage-specific genes and genes with MAE or SKE seem to make up overlapping classes subject to selection for increased diversity. The implications of these results for development and evolution are discussed in the context of a model with stochastic epigenetic modifications taking place only during a relatively brief developmental window.

scholarly journals Genetic variation of populations of Citrus psorosis virus

2006 ◽  
Vol 87 (10) ◽  
pp. 3097-3102 ◽  
Author(s):  
Susana Martín ◽  
María Laura García ◽  
Antonella Troisi ◽  
Luis Rubio ◽  
Gonzalo Legarreta ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Type Species ◽  
Protein Gene ◽  
Nucleotide Substitutions ◽  
Coding Regions ◽  
Citrus Psorosis Virus ◽  
Selection For ◽  
Genomic Regions ◽  
Two Populations ◽  
Amino Acid Sequence Conservation

Citrus psorosis virus (CPsV), the type species of genus Ophiovirus, has a segmented, negative-stranded RNA genome. We examined the population structure and genetic variation of CPsV in three coding regions located in RNAs 1, 2 and 3, analysing 22 isolates from Argentina, California, Florida, Italy and Spain. Most isolates contained a predominant sequence and some minor variants. Estimations of the genetic diversity and phylogenetic clustering of isolates disclosed two populations, one comprising isolates from Spain, Italy, Florida and California and the other including the Argentinean isolates. Isolate CPV-4 (from Texas) included for comparison was distant from both groups, suggesting that it belongs to a third group. The low ratio between non-synonymous and synonymous nucleotide substitutions indicated strong selection for amino acid sequence conservation, particularly in the coat protein gene. Incongruent phylogenetic relationships in different genomic regions suggested that exchange of genomic segments may have contributed to CPsV evolution.

SELECTION FOR OLEIC, LINOLEIC AND LINOLENIC ACID CONTENT IN F2 POPULATIONS OF RAPE

1976 ◽  
Vol 56 (4) ◽  
pp. 961-966 ◽  
Author(s):  
Z. P. KONDRA ◽  
T. W. WILSON
Keyword(s):  
Linolenic Acid ◽  
Acid Content ◽  
Seed Oil ◽  
Linoleic Acid Content ◽  
Linolenic Acid Content ◽  
Brassica Napus L ◽  
Selection For ◽  
Lower Magnitude ◽  
Two Populations ◽  
Made In

Single plant selections for high, intermediate, and low oleic, linoleic and linolenic acid content of rapeseed (Brassica napus L.) oil were made in the F2 generation of three crosses. The three parent strains produced seed oil practically free of eicosenoic and erucic acids and differed in oleic, linoleic and linolenic acid content. The F3 and F4 progeny were analyzed for fatty acid composition. Selection for low and high values of oleic and linoleic acid content was reasonably successful in two out of three crosses. Selection for extremes of linolenic acid content was unsuccessful in all three crosses. Regression analyses indicated high heritabilities for oleic and linoleic acids in two of three crosses but low heritabilities for linolenic acid in all three crosses. Correlations between oleic versus linoleic and oleic versus linolenic were negative and highly significant. Correlations between linoleic versus linolenic were of lower magnitude but positive and significant in all but two populations.

Variation in Drought Tolerance in Eucalyptus viminalis Labill

1974 ◽  
Vol 22 (3) ◽  
pp. 489 ◽  
Author(s):  
PY Ladiges
Keyword(s):  
Drought Tolerance ◽  
Drought Resistance ◽  
Moisture Stress ◽  
Habitat Changes ◽  
Eucalyptus Viminalis ◽  
Moist Habitat ◽  
Physiological Resistance ◽  
Selection For ◽  
Granite Soil ◽  
Two Populations

Six-month-old seedlings of two low rainfall populations of Eucalyptus viminalis showed greater resistance to desiccation and were less damaged by sustained drought than seedlings from two high rainfall populations. The more resistant seedlings did not simply avoid drought by quickly closing stomata, but were capable of maintaining relatively high rates of transpiration under moderate moisture stress. The two populations from moist habitats wilted at a higher relative turgidity of leaves than did the populations from the drier habitats. Furthermore, for populations from one dry habitat and one moist habitat, changes in relative turgidity in relation to water potential of leaves during drying were not significantly different. It is suggested that the greater tolerance of the low rainfall populations to drought is related to physiological resistance of the protoplasm to desiccation. Some differences in drought resistance were also noted between the two low rainfall populations. Young seedlings (3 months old) from a population on a deep basalt-derived soil were less resistant than young seedlings from a neighbouring population on a shallower granite soil. It is suggested that the selection for drought tolerance at the granite site has been more severe than at the basalt site.

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