• Title/Summary/Keyword: Hitchhiking

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한국 섬집단에 있어서 D.melanogaster의 효소좌위와 염색체간의 연관관계

  • Kang, Young-Soon;Kim, Wook
    • The Korean Journal of Zoology
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    • v.35 no.1
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    • pp.87-95
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    • 1992
  • 한국의 세 섬집단으로부터 채집한 Drosophila melanogaster를 대상으로 465개의 haploid genome을 추출한 후, 제 2염색체 상에 위치한 Gpdh와 각서 유전자 및 In(2I)t의 빈도를 조사하여 이들간의 연관관계를 분석한 결과 Gpdh와 Adh 효소 좌위 사이 에 유의 한 연관 불평형 이 제주도와 울릉도집 단에서 관찰되었으며 , Gpdh와 In(2I)t, Adh와 In(21)t 사이에 모두 유의한 연관 불평형이 제주도, 영종도 그리고 울릉도집단에서 관찰되었다. 조사된 전체 genome들 중에서 In(21)t 를 가지고 있는 염색체의 98%(48/49)가 Gpdhf와 Adhs형으로 연관된 결과를 보였다. 이러한 결과들로 볼 때 이들 효소 좌위 사이에 나타난 연관 불평형은 In(21)t와의 hitchhiking현상에 의해 나타난 결과로 해석되며 본 섬집단에서 그 정도가 더 심한 것으로 확인되었다.

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Selection signature reveals genes associated with susceptibility loci affecting respiratory disease due to pleiotropic and hitchhiking effect in Chinese indigenous pigs

  • Xu, Zhong;Sun, Hao;Zhang, Zhe;Zhang, Cheng-Yue;Zhao, Qing-bo;Xiao, Qian;Olasege, Babatunde Shittu;Ma, Pei-Pei;Zhang, Xiang-Zhe;Wang, Qi-Shan;Pan, Yu-Chun
    • Asian-Australasian Journal of Animal Sciences
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    • v.33 no.2
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    • pp.187-196
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    • 2020
  • Objective: Porcine respiratory disease is one of the most important health problems causing significant economic losses. To understand the genetic basis for susceptibility to swine enzootic pneumonia (EP) in pigs, we detected 102,809 single nucleotide polymorphisms in a total of 249 individuals based on genome-wide sequencing data. Methods: Genome comparison of susceptibility to swine EP in three pig breeds (Jinhua, Erhualian, and Meishan) with two western lines that are considered more resistant (Duroc and Landrace) using cross-population extended haplotype homozygosity and F-statistic (FST) statistical approaches identified 691 positively selected genes. Based on quantitative trait loci, gene ontology terms and literature search, we selected 14 candidate genes that have convincible biological functions associated with swine EP or human asthma. Results: Most of these genes were tested by several methods including transcription analysis and candidate genes association study. Among these genes: cytochrome P450 1A1 and catenin beta 1 (CTNNB1) are involved in fertility; transforming growth factor beta receptor 3 plays a role in meat quality traits; Wnt family member 2, CTNNB1 and transcription factor 7 take part in adipogenesis and fat deposition simultaneously; plasminogen activator, urokinase receptor (completely linked to AXL receptor tyrosine kinase, r2 = 1) plays an essential role in the successful ovulation of matured oocytes in pigs; colipase like 2 (strongly linked to SAM pointed domain containing ETS transcription factor, r2 = 0.848) is involved in male fertility. Conclusion: These adverse genes susceptible to swine EP may be selected while selecting for economic traits (especially reproduction traits) due to pleiotropic and hitchhiking effect of linked genes. Our study provided a completely new point of view to understand the genetic basis for susceptibility or resistance to swine EP in pigs thereby, provides insight for designing sustainable breed selection programs. Finally, the candidate genes are crucial due to their potential roles in respiratory diseases in a large number of species, including human.

Prevalence of negative frequency-dependent selection, revealed by incomplete selective sweeps in African populations of Drosophila melanogaster

  • Kim, Yuseob
    • BMB Reports
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    • v.51 no.1
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    • pp.1-2
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    • 2018
  • Positive selection on a new beneficial mutation generates a characteristic pattern of DNA sequence polymorphism when it reaches an intermediate allele frequency. On genome sequences of African Drosophila melanogaster, we detected such signatures of selection at 37 candidate loci and identified "sweeping haplotypes (SHs)" that are increasing or have increased rapidly in frequency due to hitchhiking. Based on geographic distribution of SH frequencies, we could infer whether selective sweeps occurred starting from de novo beneficial mutants under simple constant selective pressure. Single SHs were identified at more than half of loci. However, at many other loci, we observed multiple independent SHs, implying soft selective sweeps due to a high beneficial mutation rate or parallel evolution across space. Interestingly, SH frequencies were intermediate across multiple populations at about a quarter of the loci despite relatively low migration rates inferred between African populations. This invokes a certain form of frequency-dependent selection such as heterozygote advantage. At one locus, we observed a complex pattern of multiple independent that was compatible with recurrent frequency-dependent positive selection on new variants. In conclusion, genomic patterns of positive selection are very diverse, with equal contributions of hard and soft sweeps and a surprisingly large proportion of frequency-dependent selection in D. melanogaster populations.

Alien hitchhiker insect species detected from the international vessels entering into Korea in 2021

  • Tae Hwa Kang;Nam Hee Kim;Sang Woong Kim;Deuk-Soo Choi
    • Journal of Species Research
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    • v.12 no.2
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    • pp.189-196
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    • 2023
  • We monitored the hitchhiker insect pests from the international vessels entering into Korea in 2021. As a result, total of 581 individuals were detected by the survey based on visual inspection with naked eye. Among them, 500 individuals were identified as 244 species of 65 families under 11 orders through the integrative taxonomic method with DNA barcoding and morphological reexamination, but the remaining 81 individuals were classified as only to the family level. Of the 244 species identified, 26 species were determined to be not-distributed species in Korea (two Orthoptera, two Hemiptera, one Megaloptera, five Coleoptera, three Hymenoptera, and 13 Lepidoptera). Among them, two species, Sagra femorata (Chrysomelidae, Coleoptera) and Dendrolimus punctatus (Lasiocampidae, Lepidoptera), were discovered as 'Regulated species' listed by Animal and Plant Quarantine Agency, South Korea. Therefore, we reported on the 26 not-distributed species in Korea and provided inanimate pathway information such as navigation routes on the vessels hitchhiking the species, state of the samples at the time of detection, identification results and original distribution for the detailed monitoring and the risk analysis on the species.

Genetic assessment of BoLA-DRB3 polymorphisms by comparing Bangladesh, Ethiopian, and Korean cattle

  • Mandefro, Ayele;Sisay, Tesfaye;Edea, Zewdu;Uzzaman, Md. Rasel;Kim, Kwan-Suk;Dadi, Hailu
    • Journal of Animal Science and Technology
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    • v.63 no.2
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    • pp.248-261
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    • 2021
  • Attributable to their major function in pathogen recognition, the use of bovine leukocyte antigens (BoLA) as disease markers in immunological traits in cattle is well established. However, limited report exists on polymorphism of the BoLA gene in zebu cattle breeds by high resolution typing methods. Thus, we used a polymerase chain reaction sequence-based typing (PCR-SBT) method to sequence exon 2 of the BoLA class II DRB3 gene from 100 animals (Boran, n = 13; Sheko, n = 20; Fogera, n = 16; Horro, n = 19), Hanwoo cattle (n = 18) and Bangladesh Red Chittagong zebu (n = 14). Out of the 59 detected alleles, 43 were already deposited under the Immuno Polymorphism Database for major histocompatibility complex (IPD-MHC) while 16 were unique to this study. Assessment of the level of genetic variability at the population and sequence levels with genetic distance in the breeds considered in this study showed that Zebu breeds had a gene diversity score greater than 0.752, nucleotide diversity score greater than 0.152, and mean number of pairwise differences higher than 14, being very comparable to those investigated for other cattle breeds. Regarding neutrality tests analyzed, we investigated that all the breeds except Hanwoo had an excess number of alleles and could be expected from a recent population expansion or genetic hitchhiking. Howbeit, the observed heterozygosity was not significantly (p < 0.05) higher than the expected heterozygosity. The Hardy Weinberg equilibrium (HWE) analysis revealed non-significant excess of heterozygote animals, indicative of plausible over-dominant selection. The pairwise FST values suggested a low genetic variation among all the breeds (FST = 0.056; p < 0.05), besides the rooting from the evolutionary or domestication history of the cattle. No detached clade was observed in the evolutionary divergence study of the BoLA-DRB3 gene, inferred from the phylogenetic tree based on the maximum likelihood model. The investigation herein indicated the clear differences in BoLA-DRB3 gene variability between African and Asian cattle breeds.