Anolis Lizards of the Eastern Caribbean: A Case Study in Evolution. II. Genetic Relationships and Genetic Variation of the Bimaculatus Group

1976 ◽  
Vol 25 (1) ◽  
pp. 62 ◽  
Author(s):  
George C. Gorman ◽  
Y. J. Kim
Keyword(s):  
Genetic Variation ◽  
Genetic Relationships ◽  
Eastern Caribbean

Genetic Relationships of Cory's Shearwater: Parentage, Mating Assortment, and Geographic Differentiation Revealed by DNA Fingerprinting

The Auk ◽  
2000 ◽  
Vol 117 (3) ◽  
pp. 651-662 ◽  
Author(s):  
Corinne Rabouam ◽  
Vincent Bretagnolle ◽  
Yves Bigot ◽  
Georges Periquet
Keyword(s):  
Genetic Variation ◽  
Genetic Structure ◽  
Dna Fingerprinting ◽  
Genetic Relatedness ◽  
Isolation By Distance ◽  
Genetic Relationships ◽  
Cory’S Shearwater ◽  
Genetic Structure Of Populations ◽  
The Social ◽  
Calonectris Diomedea

Abstract We used DNA fingerprinting to assess genetic structure of populations in Cory's Shearwater (Calonectris diomedea). We analyzed mates and parent-offspring relationships, as well as the amount and distribution of genetic variation within and among populations, from the level of subcolony to subspecies. We found no evidence of extrapair fertilization, confirming that the genetic breeding system matches the social system that has been observed in the species. Mates were closely related, and the level of genetic relatedness within populations was within the range usually found in inbred populations. In contrast to previous studies based on allozymes and mtDNA polymorphism, DNA fingerprinting using microsatellites revealed consistent levels of genetic differentiation among populations. However, analyzing the two subspecies separately revealed that the pattern of genetic variation among populations did not support the model of isolation by distance. Natal dispersal, as well as historic and/or demographic events, probably contributed to shape the genetic structure of populations in the species.

scholarly journals Parasite variation and the evolution of virulence in a Daphnia-microparasite system

Parasitology ◽  
2007 ◽  
Vol 135 (3) ◽  
pp. 303-308 ◽  
Author(s):  
T. J. LITTLE ◽  
W. CHADWICK ◽  
K. WATT
Keyword(s):  
Genetic Variation ◽  
Rank Order ◽  
Genetic Relationships ◽  
Natural Populations ◽  
Host Genotype ◽  
Relative Growth ◽  
Trade Off ◽  
Relative Growth Rates ◽  
Pasteuria Ramosa ◽  
Evolution Of Virulence

SUMMARYUnderstanding genetic relationships amongst the life-history traits of parasites is crucial for testing hypotheses on the evolution of virulence. This study therefore examined variation between parasite isolates (the bacterium Pasteuria ramosa) from the crustacean Daphnia magna. From a single wild-caught infected host we obtained 2 P. ramosa isolates that differed substantially in the mortality they caused. Surprisingly, the isolate causing higher early mortality was, on average, less successful at establishing infections and had a slower growth rate within hosts. The observation that within-host replication rate was negatively correlated with mortality could violate a central assumption of the trade-off hypothesis for the evolution of virulence, but we discuss a number of caveats which caution against premature rejection of the trade-off hypothesis. We sought to test if the characteristics of these parasite isolates were constant across host genotypes in a second experiment that included 2 Daphnia host clones. The relative growth rates of the two parasite isolates did indeed depend on the host genotype (although the rank order did not change). We suggest that testing evolutionary hypotheses for virulence may require substantial sampling of both host and parasite genetic variation, and discuss how selection for virulence may change with the epidemiological state of natural populations and how this can promote genetic variation for virulence.

Habitat differentiation between estuarine and inland Hibiscus tiliaceus L. (Malvaceae) as revealed by retrotransposon-based SSAP marker

2011 ◽  
Vol 59 (6) ◽  
pp. 515 ◽  
Author(s):  
Tian Tang ◽  
Lian He ◽  
Feng Peng ◽  
Suhua Shi
Keyword(s):  
Genetic Variation ◽  
Gene Flow ◽  
Genetic Distance ◽  
Genetic Variance ◽  
Genetic Relationships ◽  
Principal Coordinate Analysis ◽  
Geographical Isolation ◽  
Tidal Zone ◽  
Ecological Scale ◽  
Habitat Differentiation

Hibiscus tiliaceus L. (Malvaceae) is a pantropical coastal tree that extends to the tidal zone. In this study, the retrotransposon sequence-specific amplified polymorphism (SSAP) technique was used in order to understand the genetic variation between four population pairs of H. tiliaceus from repeated estuarine and inland habitat contrasts in China. The estuarine populations were consistently more genetic variable compared with the inland ones, which may be attributed to extensive gene flow via water-drifted seeds and/or retrotransposon activation in stressful estuarine environments. An AMOVA revealed that 8.9% of the genetic variance could be explained by the habitat divergence within site, as compared with only 4.9% to geographical isolation between sites, which indicates significant habitat differentiation between the estuarine and inland populations. The estuarine populations were less differentiated (ΦST = 0.115) than the inland (ΦST = 0.152) implying frequent gene interchange in the former. Accordingly, the principal coordinate analysis of genetic distance between individuals revealed that genetic relationships are not fully consistent with the geographic association. These results suggest that despite substantial gene flow via sea-drifted seeds, habitat-related divergent selection could be one of the primary mechanisms that drive habitat differentiation in H. tiliaceus at a local ecological scale.

scholarly journals Evaluating the genetic variability of rubber hybrid progenies of the two crosses PB260 x RO44/71 and PB260 x RO62/54 by RAPD technique

2019 ◽  
Vol 2 (3) ◽  
pp. 36-43
Author(s):  
Thien Minh Nguyen ◽  
Tien Thi My Pham
Keyword(s):  
Genetic Variation ◽  
Genetic Variability ◽  
Genetic Similarity ◽  
Field Experiments ◽  
Agronomic Traits ◽  
Genetic Relationships ◽  
Genetic Material ◽  
Population Based ◽  
Shannon Index ◽  
Polymorphic Bands

The agronomic values of this population have been evaluated in the field experiments based on their phenotypic performance of agronomic traits, but the genetic variability of this population needs to be evaluated via techniques based on genetic material - DNA. In this study, the genetic variability in the investigated population of 71 hybrids and their parents was evaluated by RAPD technique, using eight selected arbitrarily primers; Genetic parameters and dendrogram expressing the genetic relationships among the investigated population were analyzed by GenALEx 6.1, Popgene 1.31 and NTSYSpc 2.1 softwares. Eight primers were used to generate the amplify products on each individual in the investigated population. From 74 genotypes, a total of 109 fragments were generated, among which, there were 89 polymorphic bands representing 81.65% with an average of 11 polymorphic bands/primer. Genetic similarity coefficient among the investigated population, based on DICE coefficient, ranged from 0.560 (LH05/0822 and PB260) to 0.991 (LH05/0781 and LH05/0841) with an average of 0,796, meaning that the genetic distance among ranged from 0.009 to 0.440 with an average of 0.231. The Shannon index and mean heterozygosity values were 0.328 and 0,176, respectively. This indicated that the progenies of the two investigated crosses possessed a relatively high range of genetic variability. The analysis of molecular variance (AMOVA) showed that genetic variation within population represented 62%, while genetic variation among two different crosses contributes 38% to the total genetic variability. Dendrogram based on DICE’s genetic similarity using UPGMA method showed that the hybrids divide into two major genetic groups (0.75), but the crosses were scattered independently of the hybrid.

Genetic diversity and population structure of Tarek (Alburnus tarichi), an endemic species to the Lake Van basin, Turkey

2021 ◽  
Vol 34 ◽  
pp. 3
Author(s):  
Yılmaz Çiftci ◽  
Oğuzhan Eroğlu ◽  
Şirin Firidin ◽  
Hacı Savaş ◽  
Yusuf Bektaş
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Genetic Relationships ◽  
Significance Test ◽  
Management Plan ◽  
Lake Van ◽  
Essential Information ◽  
Low Level ◽  
Lake Van Basin ◽  
Sustainable Fishery

In this study, the genetic relationships of 804 tarek (Alburnus tarichi) samples from a total of 18 populations, including the potamodromus and resident individuals from Lake Van basin in eastern Turkey, were studied by using nine microsatellite loci. A total of 93 alleles was detected, and the average number of alleles per locus was 10.3 ± 3.39. The mean estimated observed and expected heterozygosity were 0.340 ± 0.016 and 0.362 ± 0.015, respectively, which indicated a low level of polymorphism. After Bonferroni correction (P < 0.0027), the multi-locus test applied to each population revealed that 12 out of 18 populations were in Hardy-Weinberg equilibrium (HWE) (P = 0.0120–0.9981). Analysis of molecular variance (AMOVA) showed more than 76% genetic variability within individuals and 19% among populations, which was significantly higher than zero (FST = 0.19), and furthermore, a low level of genetic variation was observed among individuals within populations (4.84%: FIS = 0.06). Bayesian clustering analysis indicated that the total genetic variation grouped into 3 clusters. Additionally, the significance test results revealed that 11 of the 18 populations are threatened with extinction due to recent bottleneck events.We conclude that the tarek populations from the Lake Van basin can be classified into distinct genetic groups, based on microsatellite information. In addition, our results provide essential information for the development of a management plan that conserves the tarek's genetic diversity and achieves a sustainable fishery.

Wild proso millet (Panicum miliaceum) is genetically variable and distinct from crop varieties of proso millet

Weed Science ◽  
1997 ◽  
Vol 45 (4) ◽  
pp. 509-518 ◽  
Author(s):  
Joseph C. Colosi ◽  
Barbara A. Schaal
Keyword(s):  
Genetic Variation ◽  
North America ◽  
Genetic Relationships ◽  
Random Amplified Polymorphic Dna ◽  
Large Area ◽  
Row Crops ◽  
Multiple Introductions ◽  
Proso Millet ◽  
Crop Varieties ◽  
Two Hybrid

Proso millet occurs both as a crop and a weed in North America. In 1970, an olive-black seeded biotype called ‘wild proso millet’ was found as an aggressive weed in row crops in Minnesota and Wisconsin and has since spread over a large area. We used Random Amplified Polymorphic DNA (RAPD) to assess genetic relationships among biotypes, measure genetic variation within wild proso millet across its range, and detect hybridization between wild proso millet and crop biotypes of proso millet. We found 97 RAPD genotypes among 398 individuals: 69 wild proso millet genotypes, 26 crop and crop-like weed genotypes, and two hybrid genotypes. Five RAPD markers consistently differentiated wild proso millet from crop cultivars and crop-like weeds. About 10% of the genotypes had at least one marker of the other type, suggesting possible hybridization between wild proso millet and crop biotypes. Most genotypes occurred in only one or two of the over 100 populations tested. The most widespread wild proso millet genotype occurred in 12 populations distributed in North Dakota, Minnesota, Illinois, and Wisconsin. More genetic variation exists among populations of wild proso millet than expected for a plant that presumably experienced a severe genetic bottleneck only 20 generations ago. Hypermutation rates and crossing between wild proso millet and crop cultivars could not account for the degree of genetic variation found in wild proso millet. The pattern of genetic variation among wild proso millet populations suggests multiple introductions of wild proso millet to North America.

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