Geographic variation in seedling morphology of Casuarina equisetifolia subsp. equisetifolia (Casuarinaceae)

2016 ◽  
Vol 64 (2) ◽  
pp. 160 ◽  
Author(s):  
Pan Hu ◽  
Chonglu Zhong ◽  
Yong Zhang ◽  
Qingbin Jiang ◽  
Yu Chen ◽  
...  

Seeds collected from 28 natural provenances and introduced populations of Casuarina equisetifolia subsp. equisetifolia L. from Oceania, Asia and Africa were used to study geographic variation in growth and morphology of nursery-grown seedlings. Ten characteristics related to growth and branching habit were measured for each seedling and the resultant data subjected to univariate and multivariate analyses. In general, seedlings from Oceania grew more slowly, were more densely branched with fine and upright branching, and had fewer teeth per whorl than those from other areas. Cluster analysis effectively separated Oceania from Asian natural provenances, and revealed the probable original sources of introductions to different parts of Asia and Africa. Further investigation into the pattern of variation through molecular characterisation of genetic material from all major regions of distribution is warranted in order to better understand the genetic relationships and enhance more efficient utilisation of this important casuarina species.

2002 ◽  
Vol 50 (3) ◽  
pp. 319 ◽  
Author(s):  
A. Kalinganire ◽  
K. Pinyopusarerk ◽  
E. R. Williams

Seed collected from 23 native provenances of Chukrasia A.Juss. and one Australian land race was used to study geographic variation in seedling morphology under temperature-controlled glasshouse conditions. Twenty-four variates were measured for each seedling and the resultant data subjected to univariate and multivariate analyses. The multivariate analyses effectively separated the Chukrasia genus into three different groups or eco-geographical clusters. The most important characteristics that separated the groups were bark structure, leaf type and midrib colour. The first group, provenances from China, Laos, Malaysia, Vietnam and the Australian land race, is characterised by smooth bark, pinnate or intermediate leaves and reddish-green to greenish-red midrib. The second group, provenances from Myanmar and Thailand, is characterised by rough bark, mainly bipinnate leaves and green midrib. The third group, provenances from Sri Lanka, is characterised by rough bark, bipinnate leaves and red midrib. The study clearly shows Chukrasia to be a polymorphic species comprising at least three ecotypes or possibly three ecospecies. A study of allozyme variation may better reveal the systematics within the genus.


1991 ◽  
Vol 39 (3) ◽  
pp. 247 ◽  
Author(s):  
K Pinyopusarerk ◽  
ER Williams ◽  
DJ Boland

Seedlings from 30 provenances from Papua New Guinea, Queensland and the Northern Territory, Australia, (and two from Thailand) were raised under common glasshouse conditions. Seventeen attributes were measured for each seedling and the resultant data subjected to univariate and multivariate analyses. Provenance differences were evident; variation amongst families within provenances was generally small. The Papua New Guinea, Queensland and Northern Territory material clustered into three distinct groups. There was a suggestion that the Queensland and Northern Territory populations were more closely related to each other than to those from Papua New Guinea. The Thai populations possibly came originally as seed from Queensland.


Author(s):  
J. Grahame ◽  
P. J. Mill ◽  
M. Double ◽  
S. L. Hull

Johannesson & Johannesson (1993) contend that we have misread their earlier paper (Johannesson & Johannesson, 1990). They write that it is only possible to use neutral loci to study genetic relationships in closely related taxa (Johannesson & Johannesson, 1993) and that, there-fore, they had dismissed the variation in Aat-1 when considering the taxonomic status of Littorina neglecta (Johannesson & Johannesson, 1993). However, in their earlier paper they write: & ldquo;This [the pattern of variation in Aat-1] indicates that the within-site differentiation at Aat-1 is caused by diversifying selection in the two different micro-habitats rather than to a reproductive barrier between neglecta and saxatilis type snails” (Johannesson & Johannesson, 1990, p. 94). Therefore, after dealing separately with the pattern of variation at four loci which are ‘presumably neutral’ (Johannesson & Johannesson, 1990, p. 96), the Aat-1 variation is considered by these authors in the context of a putative reproductive barrier. The argument is repeated at the beginning of the discussion in Johannesson & Johannesson (1990, p. 95).


2010 ◽  
Vol 36 (8) ◽  
pp. 873-884 ◽  
Author(s):  
Santiago R. Ramírez ◽  
Thomas Eltz ◽  
Falko Fritzsch ◽  
Robert Pemberton ◽  
Elizabeth G. Pringle ◽  
...  

1953 ◽  
Vol 31 (3) ◽  
pp. 211-225 ◽  
Author(s):  
C. C. Lindsey

Anal fin rays were counted on 4766 specimens of Richardsonius balteatus from 61 localities in British Columbia. Individual counts varied from 10 to 21, and mean counts of different populations varied from 12.06 to 17.51. Significant differences in counts occurred between different bodies of water, between recently introduced populations and their parent stock, between different parts of the same lake, and between different year classes. Ray counts tended to be higher amongst females in populations with high over-all means, and higher amongst males in populations with low over-all means. A positive correlation was demonstrated between water temperatures recorded in the vicinity of developing fry and the mean numbers of anal rays produced. Within each latitudinal zone a similar correlation occurred between mean ray count and average air temperature during the spawning season, but data on 109 means of populations in U.S.A. and Canada indicated a tendency, probably genetic, towards production, at equivalent temperature, of higher ray count towards the northern end of the range. Loose correlations between anal ray count and certain other morphological characteristics suggest that these may be dependent on more or less common environmental factors but are not linked by direct causality.


Author(s):  
Thien Minh Nguyen ◽  
Tien Thi My Pham

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.


2020 ◽  
Vol 24 (7) ◽  
pp. 747-754
Author(s):  
V. R. Kharzinova ◽  
N. A. Zinovieva

One of the main tasks of genetics and animal breeding is the assessment of genetic diversity and the study of genetic relationships between different breeds and populations using molecular genetic analysis methods. We analysed the polymorphism of microsatellites and the information on the state of genetic diversity and the population structure of local breeds in Russia: the Kemerovo, the Berkshire, the Liven, the Mangalitsa, and the Civilian; in the Republic of Belarus: the Large White and the Black-and-White; and in Ukraine: the White Steppe, as well as commercial breeds of imported origin of domestic reproduction: the Large White, the Landrace, and the Duroc. The materials used for this study were the tissue and DNA samples extracted from 1,194 pigs and DNA of the UNU “Genetic material bank of domestic and wild animal species and birds” of the L.K. Ernst Federal Research Center for Animal Husbandry. Polymorphisms of 10 microsatellites (S0155, S0355, S0386, SW24, SO005, SW72, SW951, S0101, SW240, and SW857) were determined according to the previously developed technique using DNA analyser ABI3130xl. To estimate the allele pool of each population, the average number of alleles (NA), the effective number of alleles (NE ) based on the locus, the rarified allelic richness (AR), the observed (HO ) and expected (HE ) heterozygosity, and the fixation index (FIS) were calculated. The degree of genetic differentiation of the breeds was assessed based on the pairwise values of FST and D. The analysis of the allelic and genetic diversity parameters of the local breeds showed that the maximum and minimum levels of polymorphism were observed in pigs of the Ukrainian White Steppe breed (NA = 6.500, NE = 3.709, and AR = 6.020) and in pigs of the Duroc breed (NA = 4.875, NE = 2.119, and AR = 3.821), respectively. The highest level of genetic diversity was found in the Large White breed of the Republic of Belarus (HO = 0.707 and NE = 0.702). The minimum level of genetic diversity was found in pigs of the imported breeds – the Landrace (HO = 0.459, HE = 0.400) and the Duroc (HO = 0.480, HE = 0.469) – indicating a high selection pressure in these breeds. Based on the results of phylogenetic analysis, the genetic origin of Large White pigs, the breeds, from which the Berkshire pigs originated, and the genetic detachment of the Landrace from the Mangalitsa breeds were revealed. The cluster analysis showed a genetic consolidation of the Black-and-White, the Berkshire, and the Mangalitsa pigs. Additionally, the imported breeds with clustering depending on the origin were characterised by a genetic structure different from that of the other breeds. The information obtained from these studies can serve as a guide for the management and breeding strategies of the pig breeds studied, to allow their better use and conservation.


2019 ◽  
Vol 18 (2) ◽  
pp. 195-207
Author(s):  
Carolina Nisa Ramiro ◽  
Renato Sousa Recoder ◽  
Miguel Trefaut Rodrigues

Geographic variation in the morphology of the sand-dwelling lizard Nothobachia ablephara (Squamata: Gymnophthalmidae). Nothobachia ablephara is a small microteiid lizard with an elongated body and reduced limbs; it occurs in isolated dune felds in the state of Bahia (Xique-Xique and Alagoado) and small sandy patches in northeastern Brazil. A previous molecular study found a marked mtDNA divergence between populations of N. ablephara from Alagoado and Xique-Xique dunes, suggesting that the two populations diverged from one another between 3 and 4 million years ago. Given this isolation, it is interesting to explore whether morphological traits of the lizards refect the reported genetic divergence of the populations. Scale counts of the sexes and the populations differ signifcantly, but there is considerable overlap of values. Univariate and multivariate analyses revealed signifcant morphometric variation between sexes and populations; however, this is mostly explained by size differences. Females are larger than males in all characters that are sexually dimorphic, and individuals from Xique-Xique are larger than those from Alagoado in all characters that vary geographically. The sample from Alagoado has more sexually dimorphic characters than the one from Xique-Xique. Although N. ablephara displays some geographical variation, the two populations could not be unequivocally distinguished by scale counts and morphometric data.


Zootaxa ◽  
2005 ◽  
Vol 1013 (1) ◽  
pp. 19 ◽  
Author(s):  
PAULO PASSOS ◽  
RONALDO FERNANDES ◽  
MARCOVAN PORTO

The taxonomic status of Dipsas albifrons is revised and geographic variation of external morphology and hemipenis are described. Multivariate analyses suggest that the pattern of geographical variation is correlated with gap sampling, probably indicating a northernward cline in segmental counts (mainly ventral and subcaudal scales). Quantitative and qualitative analyses reveal that the island population (Dipsas albifrons cavalheiroi) is not divergent from mainland populations and, herein, is considered a junior synonymy of Dipsas albifrons. A lectotype of Dipsas albifrons is designated.


mBio ◽  
2010 ◽  
Vol 1 (3) ◽  
Author(s):  
Vladimir Trifonov ◽  
Raul Rabadan

ABSTRACT Environmental metagenomic samples and samples obtained as an attempt to identify a pathogen associated with the emergence of a novel infectious disease are important sources of novel microorganisms. The low costs and high throughput of sequencing technologies are expected to allow for the genetic material in those samples to be sequenced and the genomes of the novel microorganisms to be identified by alignment to those in a database of known genomes. Yet, for various biological and technical reasons, such alignment might not always be possible. We investigate a frequency analysis technique which on one hand allows for the identification of genetic material without relying on alignment and on the other hand makes possible the discovery of nonoverlapping contigs from the same organism. The technique is based on obtaining signatures of the genetic data and defining a distance/similarity measure between signatures. More precisely, the signatures of the genetic data are the frequencies of k-mers occurring in them, with k being a natural number. We considered an entropy-based distance between signatures, similar to the Kullback-Leibler distance in information theory, and investigated its ability to categorize negative-sense single-stranded RNA (ssRNA) viral genetic data. Our conclusion is that in this viral context, the technique provides a viable way of discovering genetic relationships without relying on alignment. We envision that our approach will be applicable to other microbial genetic contexts, e.g., other types of viruses, and will be an important tool in the discovery of novel microorganisms. IMPORTANCE Multiple factors contribute to the emergence of novel infectious diseases. Implementation of effective measures against such diseases relies on the rapid identification of novel pathogens. Another important source of novel microorganisms is environmental metagenomic samples. The low costs and high throughput of sequencing technologies provide a method for the identification of novel microorganisms by sequence alignment. There are several obstacles to this method, as follows: our knowledge of biology is biased by an anthropomorphic view, microbial genomic material could be a minuscule fraction of the sample, the sequencing and enrichment technologies can be a source of errors and biases, and finally, microbes have high diversity and high evolutionary rates. As a result, novel microorganisms could have very low genetic similarity to already known genomes, and the identification by alignment could be computationally prohibitive. We investigate a frequency analysis technique which allows for the identification of novel genetic material without relying on alignment.


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