scholarly journals Genome of the Southern Giant Petrel Assembled Using Third-Generation DNA Sequencing and Linked Reads Reveals Evolutionary Traits of Southern Avian

Animals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 2046
Author(s):  
Sun-Hee Kim ◽  
Seung-Jae Lee ◽  
Euna Jo ◽  
Jangyeon Kim ◽  
Jong-U Kim ◽  
...  
Keyword(s):  
Population Size ◽  
Effective Population Size ◽  
Single Molecule ◽  
Early Pleistocene ◽  
Size Analysis ◽  
Comparative Genomic ◽  
Giant Petrel ◽  
Effective Population ◽  
Functional Studies ◽  
Southern Giant Petrel

The southern giant petrel Macronectes giganteus, a large seabird of the southern oceans, is one of only two members of the genus Macronectes and is the largest species in the order Procellariiformes. Although these two families account for the vast majority of the avian fauna inhabiting the Antarctic and sub-Antarctic regions, studies on the status of some populations and the associated genetic data are currently extremely limited. In this study, we assembled the genome of M. giganteus by integrating Pacific Biosciences single-molecule real-time sequencing and the Chromium system developed by 10x Genomics. The final M. giganteus genome assembly was 1.248 Gb in size with a scaffold N50 length of 27.4 Mb and a longest scaffold length of 120.4 Mb. The M. giganteus genome contains 14,993 predicted protein-coding genes and has 11.06% repeat sequences. Estimated historical effective population size analysis indicated that the southern giant petrel underwent a severe reduction in effective population size during a period coinciding with the early Pleistocene. The availability of this newly sequenced genome will facilitate more effective genetic monitoring of threatened species. Furthermore, the genome will provide a valuable resource for gene functional studies and further comparative genomic studies on the life history and ecological traits of specific avian species.

scholarly journals Genetic Diversity of Indigenous Pigs from South China Area Revealed by SNP Array

Animals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 361 ◽  
Author(s):  
Shuqi Diao ◽  
Shuwen Huang ◽  
Zhiting Xu ◽  
Shaopan Ye ◽  
Xiaolong Yuan ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Size ◽  
Effective Population Size ◽  
Conservation Status ◽  
Snp Array ◽  
Size Analysis ◽  
Selection Signatures ◽  
Effective Population ◽  
Low Genetic Diversity ◽  
Indigenous Pigs

To investigate the genetic diversity, population structure, extent of linkage disequilibrium (LD), effective population size (Ne), and selection signatures in indigenous pigs from Guangdong and Guangxi in China, 226 pigs belonging to ten diverse populations were genotyped using single nucleotide polymorphism (SNP) chips. The genetic divergence between Chinese and Western pigs was determined based on the SNP chip data. Low genetic diversity of Dahuabai (DHB), Luchuan (LC), Lantang (LT), and Meihua (MH) pigs, and introgression of Western pigs into Longlin (LL), MH, and Yuedonghei (YDH) pigs were detected. Analysis of the extent of LD showed that indigenous pigs had low LD when pairwise SNP distance was short and high LD when pairwise SNP distance was long. Effective population size analysis showed a rapid decrease for Chinese indigenous pigs, and some pig populations had a relatively small Ne. This result indicated the loss of genetic diversity in indigenous pigs, and introgression from Western commercial pigs. Selection signatures detected in this study overlapped with meat quality traits, such as drip loss, intramuscular fat content, meat color b*, and average backfat thickness. Our study deepened understanding of the conservation status and domestication of Chinese indigenous pigs.

scholarly journals A phylogenetic estimator of effective population size or mutation rate.

Genetics ◽  
1994 ◽  
Vol 136 (2) ◽  
pp. 685-692 ◽  
Author(s):  
Y X Fu
Keyword(s):  
Population Size ◽  
Effective Population Size ◽  
Mutation Rate ◽  
Dna Sequences ◽  
High Efficiency ◽  
Minimum Variance ◽  
Population Subdivision ◽  
Effective Population ◽  
Fisher Model ◽  
Mitochondrial Sequences

Abstract A new estimator of the essential parameter theta = 4Ne mu from DNA polymorphism data is developed under the neutral Wright-Fisher model without recombination and population subdivision, where Ne is the effective population size and mu is the mutation rate per locus per generation. The new estimator has a variance only slightly larger than the minimum variance of all possible unbiased estimators of the parameter and is substantially smaller than that of any existing estimator. The high efficiency of the new estimator is achieved by making full use of phylogenetic information in a sample of DNA sequences from a population. An example of estimating theta by the new method is presented using the mitochondrial sequences from an American Indian population.

scholarly journals Alu Evolution in Human Populations: Using the Coalescent to Estimate Effective Population Size

Genetics ◽  
1997 ◽  
Vol 147 (4) ◽  
pp. 1977-1982
Author(s):  
Stephen T Sherry ◽  
Henry C Harpending ◽  
Mark A Batzer ◽  
Mark Stoneking
Keyword(s):  
Population Size ◽  
Effective Population Size ◽  
Genomic Library ◽  
Diploid Cell ◽  
Human Populations ◽  
Effective Population ◽  
Alu Repeats ◽  
Branch Lengths ◽  
Diploid Cell Line ◽  
Coalescence Theory

Abstract There are estimated to be ~1000 members of the Ya5 Alu subfamily of retroposons in humans. This Subfamily has a distribution restricted to humans, with a few copies in gorillas and chimpanzees. Fifty-seven Ya5 elements were previously cloned from a HeLaderived randomly sheared total genomic library, sequenced, and screened for polymorphism in a panel of 120 unrelated humans. Forty-four of the 57 cloned Alu repeats were monomorphic in the sample and 13 Alu repeats were dimorphic for insertion presence/absence. The observed distribution of sample frequencies of the 13 dimorphic elements is consistent with the theoretical expectation for elements ascertained in a single diploid cell line. Coalescence theory is used to compute expected total pedigree branch lengths for monomorphic and dimorphic elements, leading to an estimate of human effective population size of ~18,000 during the last one to two million years.

scholarly journals DNA Sequence Variation and the Recombinational Landscape in Drosophila pseudoobscura: A Study of the Second Chromosome

Genetics ◽  
1999 ◽  
Vol 153 (2) ◽  
pp. 859-869 ◽  
Author(s):  
Martha T Hamblin ◽  
Charles F Aquadro
Keyword(s):  
Population Size ◽  
Effective Population Size ◽  
Dna Sequence ◽  
Sequence Variation ◽  
Population Expansion ◽  
Drosophila Pseudoobscura ◽  
Effective Population ◽  
Standing Variation ◽  
Dna Sequence Polymorphism ◽  
Slightly Deleterious Mutations

Abstract The relationship between rates of recombination and DNA sequence polymorphism was analyzed for the second chromosome of Drosophila pseudoobscura. We constructed integrated genetic and physical maps of this chromosome using molecular markers at 10 loci spanning most of its physical length. The total length of the map was 128.2 cM, almost twice that of the homologous chromosome arm (3R) in D. melanogaster. There appears to be very little centromeric suppression of recombination, and rates of recombination are quite uniform across most of the chromosome. Levels of sequence variation (θW, based on the number of segregating sites) at seven loci (tropomyosin 1, Rhodopsin 3, Rhodopsin 1, bicoid, Xanthine dehydrogenase, Myosin light chain 1, and ribosomal protein 49) varied from 0.0036 to 0.0167. Generally consistent with earlier studies, the average estimate of θW at total sites is 1.5-fold higher than that in D. melanogaster, while average θW at silent sites is almost 3-fold higher. These estimates of variation were analyzed in the context of a background selection model under the same parameters of mutation rate and selection as have been proposed for D. melanogaster. It is likely that a significant fraction of the higher level of sequence variation in D. pseudoobscura can be explained by differences in regional rates of recombination rather than a larger species-level effective population size. However, the distribution of variation among synonymous, nonsynonymous, and noncoding sites appears to be quite different between the species, making direct comparisons of neutral variation, and hence inferences about effective population size, difficult. Tajima’s D statistics for 6 out of the 7 loci surveyed are negative, suggesting that D. pseudoobscura may have experienced a rapid population expansion in the recent past or, alternatively, that slightly deleterious mutations constitute an important component of standing variation in this species.

scholarly journals Low effective population size and high spatial genetic structure of black poplar populations from the Oder valley in Poland

2021 ◽  
Vol 78 (2) ◽  
Author(s):  
Błażej Wójkiewicz ◽  
Andrzewj Lewandowski ◽  
Weronika B. Żukowska ◽  
Monika Litkowiec ◽  
Witold Wachowiak
Keyword(s):  
Genetic Structure ◽  
Genetic Resources ◽  
Population Size ◽  
Effective Population Size ◽  
Spatial Genetic Structure ◽  
Demographic History ◽  
River Valley ◽  
Ex Situ ◽  
Effective Population ◽  
Black Poplar

Abstract Context Black poplar (Populus nigra L.) is a keystone species of European riparian ecosystems that has been negatively impacted by riverside urbanization for centuries. Consequently, it has become an endangered tree species in many European countries. The establishment of a suitable rescue plan of the remaining black poplar forest stands requires a preliminary knowledge about the distribution of genetic variation among species populations. However, for some parts of the P. nigra distribution in Europe, the genetic resources and demographic history remain poorly recognized. Aims Here, we present the first study on identifying and characterizing the genetic resources of black poplar from the Oder valley in Poland. This study (1) assessed the genetic variability and effective population size of populations and (2) examined whether gene flow is limited by distance or there is a single migrant pool along the studied river system. Methods A total of 582 poplar trees derived from nine black poplar populations were investigated with nuclear microsatellite markers. Results (1) The allelic richness and heterozygosity level were high and comparable between populations. (2) The genetic structure of the studied poplar stands was not homogenous. (3) The signatures of past bottlenecks were detected. Conclusion Our study (1) provides evidence for genetic substructuring of natural black poplar populations from the studied river catchment, which is not a frequent phenomenon reported for this species in Europe, and (2) indicates which poplar stands may serve as new genetic conservation units (GCUs) of this species in Europe. Key message The genetic resources of black poplar in the Oder River valley are still substantial compared to those reported for rivers in Western Europe. On the other hand, clear signals of isolation by distance and genetic erosion reflected in small effective population sizes and high spatial genetic structure of the analyzed populations were detected. Based on these findings, we recommend the in situ and ex situ conservation strategies for conserving and restoring the genetic resources of black poplar populations in this strongly transformed by human river valley ecosystem.

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