scholarly journals Genetic variability of broodstocks of Tambaqui (Teleostei – Characidae) from the northeast region of Brazil

2015 ◽  
Vol 36 (6) ◽  
pp. 4013 ◽  
Author(s):  
Nelson Mauricio Lopera-Barrero ◽  
Maria Del Pilar Rodriguez-Rodriguez ◽  
Darci Carlos Fornari ◽  
Emiko Kawakami de Resende ◽  
Angela Rocio Poveda-Parra ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Variability ◽  
Genetic Differentiation ◽  
Genetic Distance ◽  
Fish Farming ◽  
Population Variability ◽  
Colossoma Macropomum ◽  
Northeast Region ◽  
Shortest Distance

The objective of this experiment was to evaluate the genetic diversity within three Tambaqui broodstocks (Colossoma macropomum). Eight primers were used to analyze 67 individuals collected from three fish farming in the municipalities: Porto Real do Colégio – Alagoas (PRC), Araujo 1 – Sergipe (AR1) and Araujo 2 – Sergipe (AR2), in Brazil. Differences in the frequencies of 88 fragments and four exclusive fragments in PRC were found. High polymorphism values (from 54.38% to 64.38%) and Shannon´s index (from 0.33 to 0.37) were observed. The AMOVA showed that high variation is within each broodstock. The identity and the genetic distance among the groups ranged from 0.845 to 0.975 and from 0.025 to 0.156 respectively, and the shortest distance was found in the groups PRC x AR1 and PRC x AR2. The genetic differentiation ranged from lower to higher (Fst = 0.03 and 0.178) as well as the migratory number per generation (Nm = 5.07 to 12.8). In general, the broodstocks had high intra-population variability, and high differentiation and genetic distance within themselves.

Genetic differentiation of regional populations of the widespread Asiatic toad (Bufo gargarizans), as revealed by development of novel microsatellite markers

2018 ◽  
Vol 66 (6) ◽  
pp. 335
Author(s):  
T. Pan ◽  
P. Yan ◽  
M. Yang ◽  
H. Wang ◽  
I. Ali ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Genetic Differentiation ◽  
Genetic Distance ◽  
Yangtze River ◽  
The Yangtze River ◽  
Geographic Scale ◽  
Widespread Species ◽  
Bufo Gargarizans ◽  
Toad Bufo

Dispersal is a key component of a species’ life history, by influencing population persistence, genetic structure, adaptation and maintenance of genetic diversity. The Asiatic toad (Bufo gargarizans) is a widespread species in east Asia. However, we still have no knowledge of what kind of geographical scale equates to genetic differentiation within B. gargarizans. In this study, the population genetics of B. gargarizans was studied at five localities, with the Yangtze River running through the sampling area, in order to detect the level of genetic differentiation and the natural barriers to the species’ dispersal on a small geographic scale, by means of the development and use of novel microsatellite loci. These markers revealed a relatively high level of genetic diversity. Distinct genetic structure among populations in B. gargarizans was observed, as described by genetic distance, AMOVA, PCA and Geneland results. A weak but significant positive correlation between genetic distance and geographical distance. The combination of these findings suggests that the Yangtze River and geographic distance may act as effective barriers for B. gargarizans. These results serve as benchmark data for understanding the impacts of dispersal barriers and continued landscape research on B. gargarizans.

scholarly journals Genetic differentiation of black–spotted breed by B–system of blood group

2016 ◽  
Vol 18 (2) ◽  
Author(s):  
A. Zhmur ◽  
V. Bodnaruk
Keyword(s):  
Genetic Variability ◽  
Genetic Differentiation ◽  
Genetic Distance ◽  
Blood Group ◽  
High Frequency ◽  
Holstein Breed ◽  
Statics And Dynamics ◽  
Western Ukraine ◽  
High Level ◽  
Dairy Breed

In animals of western interbreed type allele of B–system: b (0,169), GYE'Q' (0,202), D'G'O' (0,058), G'G'' (0,058), OJ'K'O' (0,054), Q' (0,045) and I2 (0,041) have the highest rate. Proximity of the rate of “Holstein–Frisian” allele GYE'Q' and OJ'K'O'  of Black–Spotted cows indicated interbreed type and Holstein breed is the result of a high level holsteinization of the Western Ukrainian populations. Allele BYA'G'P'Q' G'', GTYB’D’G’Q’Y’B”, YD’G’O’, D’G’O’, G’G” , O’ are typical only Black – Spotted cattle in Western Ukraine and almost never occur in related Black – Spotted breed. The high frequency of allele b in animals of interbreed western type can be explained using sires of Estonian Black – Spotted breed whose frequency but this allele is the highest (0,263). Genetic distance between Western interbreed type, the Ukrainian Black – Spotted Dairy breed and related breeds Black – Spotted breed was: Holstein – 0,483, Western Ukraine – 0,641, Estonian – 0,661, Polish – 0,733, Russian – 0,748 and Lithuanian – 0,830. Herewith the most genetically similar animals were Western interbreed type and Holstein breed. Along with significant commonality of genetic Holstein Western type of Black – Spotted cattle Ukraine has many specific features that are its originality and further confirm the validity of its autonomous existence and improvement. The genes of blood groups reflect changes in the genome populations and cattle breeds and make it possible to determine the features of statics and dynamics of genetic variability.

A Major Disjunction in Genetic Diversity Over the Geographic Range of Acacia melanoxylon R.Br

1993 ◽  
Vol 41 (3) ◽  
pp. 355 ◽  
Author(s):  
J Playford ◽  
JC Bell ◽  
GF Moran
Keyword(s):  
Genetic Diversity ◽  
Genetic Variability ◽  
Genetic Distance ◽  
Allozyme Variation ◽  
Geographic Range ◽  
Considerable Time ◽  
High Genetic Diversity ◽  
Acacia Melanoxylon ◽  
River Region ◽  
High Level

A study of allozyme variation in Acacia melanoxylon R. Br. in 27 populations from across the geographic range of the species indicated high genetic diversity compared to other Australian trees and plants generally. Clines of increasing genetic variability with increasing latitude were found for four measures of genetic diversity. Most of the genetic diversity is found within populations but there was an unusually high level of the variation between populations (37.7%). A distinct genetic separation between the northern and southern populations was located approximately at the Hunter River region, where there is also a disjunction in the distribution of the species. The Nei (1978) genetic distance between these populations within this species is larger than observed between some plant species. Clearly the species has evolved separately in the two regions for a considerable time.

Genetic structure and proposed conservation strategy for natural populations of Calycanthus chinensis Cheng et S.Y. Chang (Calycanthaceae)

2008 ◽  
Vol 88 (1) ◽  
pp. 179-186 ◽  
Author(s):  
Chu-Chuan Fan ◽  
Nicola Pecchioni ◽  
Long-Qing Chen
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Genetic Differentiation ◽  
Genetic Distance ◽  
Gene Diversity ◽  
Genetic Relationships ◽  
Natural Populations ◽  
Population Level ◽  
Conservation Strategy ◽  
Information Index

Calycanthus chinensis Cheng et S.Y. Chang, a tertiary relic species in China, is a shade-loving and deciduous bush withan elegant shape and beautiful flower of high ornamental value. It was widely planted in gardens and miniature scapes in China.The objective of this study was to characterize the genetic variation and structure in the three extant populations of the species, in order to provide useful information for a future conservation strategy. Twenty-two of 120 RAPD primers were selected and a total of 257 stable and clear DNA fragments were scored. Calycanthus chinensis showed a lower level of genetic diversity. At the population level, the percentage of polymorphic loci, Nei's gene diversity and Shannon’s information index were 40.9%, 0.1641 and 0.2386, respectively; while at the species level, the corresponding values were 59.1%, 0.2097 and 0.3123, respectively. The estimates of genetic differentiation based on Shannon’s information index (0.2360), Nei’s gene diversity (0.2175) and AMOVA (24.94%) were very similar, and significantly higher than the average genetic differentiation reported in outcrossed spermatophyte. So it suggested high genetic differentiation emerged among populations of C. chinensis. Genetic relationships among populations were assessed by Nei’s standard genetic distance, which suggested that the Tiantai population was genetically distinct from the other two populations. Moreover, the genetic distance was significantly correlated with geographical distance among populations (r = 0.997, t > t0.05). The gene flow (Nm) was 0.8994, indicating that gene exchange among populations was restricted. A conservation strategy was proposed based on the low gene flow and habitat deterioration, which are contributing to the endangered status of this species. Key words: Genetic diversity, endangered plant, population genetics, RAPD

Evaluation of the genetic diversity and population structure of five indigenous and one introduced Chinese goose breeds using microsatellite markers

2012 ◽  
Vol 92 (4) ◽  
pp. 417-423 ◽  
Author(s):  
Jinjun Li ◽  
Qingyuan Yuan ◽  
Junda Shen ◽  
Zhengrong Tao ◽  
Guoqing Li ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Genetic Differentiation ◽  
Genetic Distance ◽  
Microsatellite Markers ◽  
Genetic Relationships ◽  
Evolutionary Relationships ◽  
Distance Estimate ◽  
Cluster Analyses ◽  
Nei's Genetic Distance

Li, J., Yuan, Q., Shen, J., Tao, Z., Li, G., Tian, Y., Wang, D., Chen, L. and Lu, L. 2012. Evaluation of the genetic diversity and population structure of five indigenous and one introduced Chinese goose breeds using microsatellite markers. Can. J. Anim. Sci. 92: 417–423. The aim of this study was to determine the genetic diversity and evolutionary relationships among five indigenous Chinese goose breeds and one introduced goose breed using 29 microsatellite markers. A total of 334 distinct alleles were observed across the six breeds, and 45 of the 334 alleles (13.5%) were unique to only one breed. The indigenous geese showed higher diversity in terms of the observed number of alleles per locus (4.48–5.90) and observed heterozygosity (0.46–0.53) compared with the introduced breed (3.97 and 0.29, respectively). The pairwise genetic differentiation (FST) between the six goose breeds ranged from 0.04 between Panshi Grey goose (PS) and Yongkang Grey goose to 0.47 between PS and Landes goose; similarly, Nei's genetic distance varied between 0.25 and 0.75. However, the FST between the indigenous Chinese goose breeds was very small. In addition, genetic distance estimate, phylogenic, and cluster analyses of the genetic relationships and population structure revealed that some indigenous goose breeds had hybridized more frequently, resulting in a loss of genetic distinctiveness.

scholarly journals Small-scale spatial genetic structure of Asarum sieboldii metapopulation in a valley

2021 ◽  
Vol 45 (1) ◽  
Author(s):  
Hyeon Jin Jeong ◽  
Jae Geun Kim
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Genetic Differentiation ◽  
Genetic Distance ◽  
Spatial Genetic Structure ◽  
Dispersal Distance ◽  
Forest Understory ◽  
Small Scale ◽  
Low Density ◽  
Stochastic Events

Abstract Background Asarum sieboldii Miq., a species of forest understory vegetation, is an herbaceous perennial belonging to the family Aristolochiaceae. The metapopulation of A. sieboldii is distributed sparsely and has a short seed dispersal distance by ants as their seed distributor. It is known that many flowers of A. sieboldii depend on self-fertilization. Because these characteristics can affect negatively in genetic structure, investigating habitat structure and assessment of genetic structure is needed. A total of 27 individuals in a valley were sampled for measuring genetic diversity, genetic distance, and genetic differentiation by RAPD-PCR. Results The habitat areas of A. sieboldii metapopulation were relatively small (3.78~33.60 m2) and population density was very low (five to seven individuals in 20×20 m quadrat). The habitat of A. sieboldii was a very shady (relative light intensity = 0.9%) and mature forest with a high evenness value (J = 0.81~0.99) and a low dominance value (D = 0.19~0.28). The total genetic diversity of A. sieboldii was quite high (h = 0.338, I = 0.506). A total of 33 band loci were observed in five selected primers, and 31 band loci (94%) were polymorphic. However, genetic differentiation along the valley was highly progressed (Gst = 0.548, Nm = 0.412). The average genetic distance between subpopulations was 0.387. The results of AMOVA showed 52.77% of variance occurs among populations, which is evidence of population structuring. Conclusions It is expected that a small-scale founder effect had occurred, an individual spread far from the original subpopulation formed a new subpopulation. However, geographical distance between individuals would have been far and genetic flow occurred only within each subpopulation because of the low density of population. This made significant genetic distance between the original and new population by distance. Although genetic diversity of A. sieboldii metapopulation is not as low as concerned, the subpopulation of A. sieboldii can disappear by stochastic events due to small subpopulation size and low density of population. To prevent genetic isolation and to enhance the stable population size, conservative efforts such as increasing the size of each subpopulation or the connection between subpopulations are needed.

scholarly journals Does marine geospatial/environmental variation affect genetic variation? A meta-analysis

2021 ◽  
Author(s):  
◽  
Daniel Cárcamo
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
New Zealand ◽  
Genetic Variability ◽  
Genetic Distance ◽  
Meta Analysis ◽  
Environmental Variation ◽  
Environmental Data ◽  
Seascape Genetics ◽  
Species Specific

<p>Genetic information is important to inform management and conservation. However, few studies have tested the relationship between genetic variation and geospatial/environmental variation across marine species. Here, I test two genetics-based ideas in evolutionary theory using data from 55 New Zealand coastal marine taxa. The Core-Periphery Hypothesis (CPH) states that populations at the centre of a species’ distribution exhibit greater genetic variability than populations at the periphery (the ‘normal’ model). Variants of this model include the ‘ramped north’ (greatest variation in the north), the ‘ramped south’ (greatest variation in the south), and the ‘abundant edge’ (greatest variation at the distributional edges, least variation at the centre). The Seascape Genetics Test (SGT) null hypothesis predicts no association between genetic variation and environmental variation. I conducted a meta-analysis of published/unpublished material on population genetic connectivity and diversity and marine environmental data to test both hypotheses. To assess the CPH, genetic data were fitted to four models (Normal, Ramped North, Ramped South, Abundant Edge). I also conducted a descriptive analysis between the genetic outcomes of the CPH and abundance records for a subset of species. The SGT involved GLM analyses using eleven geospatial/environmental variables and species-specific FST-ΦST (genetic distance) estimates plus a smaller subset of genetic diversity data. The CPH results showed that 55 of 249 tests (evaluating on average 2.9 ± 1.3 genetic indices in each of the 84 studies) fitted at least one of the four models: Ramped North (10%), Ramped South (8%), Normal (2%) and Abundant Edge (2.4%). Species-specific abundance records followed the same patterns detected by the CPH. These results indicate that edge populations (Ramped North, Ramped South, Abundant Edge) exhibit greater genetic variability than central populations amongst marine taxa from New Zealand, but that most taxa do not conform to any model (~78% of all tests were not statistically significant). For the seascape genetics multi-species analysis (comprising 498 individual tests), the FST-ΦST estimates (genetic distance estimates between pairs of populations) were mostly affected by four factors related to sea surface temperature. For genetic diversity indices the most significant predictors were latitude and longitude. Whilst different factors (e.g., physical oceanography, food availability, life-history traits and harvesting), either acting alone or acting synergistically, are likely to be important in explaining patterns of genetic diversity in New Zealand’s marine coastal species, my results indicate that variables including SST and to a lesser extent the geospatial variables (latitude and longitude) explain much of the variation in the genetic indices tested here.</p>

scholarly journals THE DYNAMICS OF GENETIC VARIABILITY IN THREE GENERATIONS OF MASS SELECTION FOR FAST GROWTH IN AFRICAN CATFISH, Clarias gariepinus ASSESSED BY MICROSATELLITE MARKERS

2015 ◽  
Vol 10 (2) ◽  
pp. 113
Author(s):  
Imron Imron ◽  
Bambang Iswanto ◽  
Huria Marnis ◽  
Rommy Suprapto ◽  
Narita Syawalia Ridzwan
Keyword(s):  
Genetic Diversity ◽  
Genetic Variability ◽  
Genetic Differentiation ◽  
Clarias Gariepinus ◽  
Breeding Program ◽  
Fixation Index ◽  
Mass Selection ◽  
African Catfish ◽  
Three Generations ◽  
Selection For

Selective breeding aiming at improving the performance of economically important traits acts by exploiting population’s phenotypic variance. Due to the relationship between phenotype and genotype, selection on phenotype may also affect the profile of genotype. This study was aimed to monitor the impact of three generations of mass selection for fast growth in African catfish, Clarias gariepinus, on genetic variability, assessed by microsatellite. A total of 350 fish representing four populations, namely a composite base population (G-0), selected lines of the first generation (G-1) to the third generation (G-3), were sampled. The samples were screened for their genetic diversity using five microsatellite loci1 namely cga01, cga02, cga03, cga05, and cga09. Several genetic parameters including number of allele (A), allelic richness (AR), observed (Ho) and expected (He) heterozygosity, and fixation index (Fis) were evaluated. The results showed that there was a slight increase in the value of diversity indices in the G-1 relative to the G-0 and to the other two generations. Among these parameters, the number of allele seemed to be the most sensitive parameter in detecting genetic changes. All populations experienced heterozygote deficit and positive fixation index indicating the phenomena of inbreeding. Overall, selection for growth for three generations in African catfish breeding program resulted in significant genetic differentiation between populations. Further, the level of genetic differentiation seemed to accumulate along with the number of generaton in breeding program. However, selection did not result in a decline in genetic diversity within population. A relatively short period of the program, along with the use a high number of broodstock (mating pairs) to produce each generation seems to be able to maintain the stability of genetic diversity of the population.

scholarly journals Genetic diversity and population structure of Meretrix petechialis in China revealed by sequence-related amplified polymorphism markers

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8723 ◽  
Author(s):  
Qiaoyue Xu ◽  
Junhong Zheng ◽  
Hongtao Nie ◽  
Qingzhi Wang ◽  
Xiwu Yan
Keyword(s):  
Genetic Diversity ◽  
Genetic Differentiation ◽  
Genetic Distance ◽  
Gene Diversity ◽  
Scientific Basis ◽  
Germplasm Resources ◽  
Polymorphic Loci ◽  
Information Index ◽  
Geographical Populations ◽  
Meretrix Petechialis

Genetic variation in nine stocks of Meretrix petechialis collected from China was analyzed using sequence-related amplified polymorphism (SRAP) markers. Eight primer pairs produced 132 polymorphic loci with an average of 16.5 loci per primer pair. A population from Jiangsu had the highest percentage of polymorphic loci at 27.27%, suggesting that these resources had a rich genetic diversity. The Nei’s gene diversity of the nine populations ranged from 0.0647 to 0.0793; a population from Shandong was the lowest and a population from North Korea the highest. The Shannon’s information index was between 0.1023 and 0.1202, with the lowest in the Shandong population and the highest in the Jiangsu population. The Nei’s unbiased genetic distance between the nine populations was 0.0243–0.0570 and the genetic similarity was 0.9446–0.9760; the genetic distance between Guangxi and Shandong populations was the furthest (0.0570) and the genetic distance between Shandong and Jiangsu populations was the closest (0.0243). Nei’s gene diversity analysis indicated that the genetic variance was mainly found within individual geographical populations, and the analysis of molecular variance revealed low but significant genetic differentiation among local and regional populations. The limited gene flow (Nm = 0.555) was inferred as a major reason for the extent of genetic differentiation in M. petechialis. The results obtained here indicated that M. petechialis have high degree of genetic diversity and the potential of further breeding with excellent germplasm resources. This study provides a scientific basis for the protection of germplasm resources and the breeding of M. petechialis.

Allozyme variation in three closely related species of Caucasian rock lizards (Lacerta)

1995 ◽  
Vol 16 (4) ◽  
pp. 331-340 ◽  
Author(s):  
Ross D. MacCulloch ◽  
F.D. Danielyan ◽  
Ilya S. Darevsky ◽  
Robert W. Murphy ◽  
Keyword(s):  
Genetic Diversity ◽  
Genetic Variability ◽  
Genetic Distance ◽  
Related Species ◽  
Allozyme Variation ◽  
Direct Count ◽  
Closely Related Species ◽  
Polymorphic Loci ◽  
Allozyme Loci ◽  
Insular Populations

AbstractGenetic diversity at 37 allozyme loci was surveyed from Lacerta valentini (4 populations), L. portschinskii and L. rudis (1 population each). The number of polymorphic loci ranged from 1 (L. valentini) to 11 (L. rudis). Mean heterozygosity (direct count) ranged from 0.003 (L. valentini) to 0.071 (L. rudis). Nei's (1978) genetic distance ranged from 0-0.03 among populations of L. valentini, 0.127-0.163 between L. valentini and L. rudis and 0.366-0.487 between L. portschinskii and the two other taxa. Indices of genetic variability for species having disjunct distributions were lower than in species with contiguous distributions, similar to the case of insular populations, which have lower values than do mainland populations.

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