Genome-wide identification of simple sequence repeats and assessment of genetic diversity in Hedychium

Abstract Background The Cucurbita genus contains important economic crops in the world, while limited molecular markers have been developed in the past years. Simple sequence repeats (SSR) markers are powerful tools for the study of genetic mapping construction, genetic diversity analysis and genome wide association. The availability of pumpkin genome information has made it possible to analyze SSRs in genome wide across three Cucurbita species. Results In this paper, based on the whole genome sequences, 34,375 SSR loci were found in C. moschata, 30,577 SSR loci were found in C. maxima and 38,104 SSR loci were found in C. pepo. C. pepo has the maximum density of SSRs with an average of 145 SSR/Mb. In general, the frequency in total SSR loci decreased with the increase of the motif length, dinucleotide motifs were the most common motifs in the three species, and for the same repeat types, the SSR frequency decreased sharply with the increase of the repeat number. Most of those SSR loci were suitable for marker development (84.75% in C. moscata, 94.53% in C. maxima and 95.09% in C. pepo). Based on those markers, we compared and analyzed the cross-species SSR markers between C. pepo and other Cucurbitaceae species by silico-PCR. Using these cross-species primers, the high collinear relationships between C. pepo and the other two species were detected, respectively. Furthermore, the application of SSR markers in genetic diversity analysis was tested in C. pepo, the results showed that they were good tools to be used in genetic diversity analysis. Conclusion In this study, the genome wide SSR markers were detected from three Cucurbita species, and some of their applications were proved by comparative genomics and genetic diversity analysis. The large number of genome-wide SSR markers and crossspecies markers would promote the basic and applied studies of Cucurbita species, such as gene mapping, QTLs mapping, comparative genomics and marker-assisted breeding.

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Genome-wide characterization of simple sequence repeats in Pyrus bretschneideri and their application in an analysis of genetic diversity in pear

BMC Genomics ◽

10.1186/s12864-018-4822-7 ◽

2018 ◽

Vol 19 (1) ◽

Cited By ~ 7

Author(s):

Huabai Xue ◽

Pujuan Zhang ◽

Ting Shi ◽

Jian Yang ◽

Long Wang ◽

...

Keyword(s):

Genetic Diversity ◽

Simple Sequence Repeats ◽

Genome Wide ◽

Simple Sequence

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Genome-wide identification of simple sequence repeats and development of polymorphic SSR markers in swamp eel (Monopterus albus)

Science Progress ◽

10.1177/00368504211035597 ◽

2021 ◽

Vol 104 (3) ◽

pp. 003685042110355

Author(s):

Hai-feng Tian ◽

Qiao-mu Hu ◽

Zhong Li

Keyword(s):

Genetic Diversity ◽

Capillary Electrophoresis ◽

Ssr Markers ◽

Simple Sequence Repeats ◽

Breeding Population ◽

Monopterus Albus ◽

Polymorphic Ssrs ◽

Genome Wide ◽

Swamp Eel ◽

Simple Sequence

Objectives: Swamp eel is one model species for sexual reversion and an aquaculture fish in China. One local strain with deep yellow and big spots of Monopterus albus has been selected for consecutive selective breeding. The objectives of this study were characterizing the Simple Sequence Repeats (SSRs) of M. albus in the assembled genome obtained recently, and developing polymorphic SSRs for future breeding programs. Methods: The genome wide SSRs were mined by using MISA software, and their types and genomic distribution patterns were investigated. Based on the available flanking sequences, primer pairs were batched developed, and Polymorphic SSRs were identified by using Polymorphic SSR Retrieval tool. The obtained polymorphic SSRs were validated by using e-PCR and capillary electrophoresis, then they were used to investigate genetic diversity of one breeding population. Results: A total of 364,802 SSRs were identified in assembled M. albus genome. The total length, density and frequency of SSRs were 8,204,641 bp, 10,259 bp/Mb, and 456.16 loci/Mb, respectively. Mononucleotide repeats were predominant among SSRs (33.33%), and AC and AAT repeats were the most abundant di- and tri-nucleotide repeats motifs. A total of 287,189 primer pairs were designed, and a high-density physical map was constructed (359.11 markers per Mb). A total of 871 polymorphic SSRs were identified, and 38 SSRs of 101 randomly selected ones were validated by using e-PCR and capillary electrophoresis. Using these 38 polymorphic SSRs, 201 alleles were detected and genetic diversity level (Na, PIC, HO, and He) was evaluated. Conclusions: The genome-wide SSRs and newly developed SSR markers will provide a useful tool for genetic mapping, diversity analysis studies in swamp eel in the future. The high level of genetic diversity (Na = 5.29, PIC = 0.5068, HO = 0.4665, He = 0.5525) but excess of homozygotes ( FIS = 0.155) in one breeding population provide baseline information for future breeding program.

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