scholarly journals Patterns of microsatellite distribution reflect the evolution of biological complexity

2018 ◽  
Author(s):  
Surabhi Srivastava ◽  
Akshay Kumar Avvaru ◽  
Divya Tej Sowpati ◽  
Rakesh K Mishra

AbstractMicrosatellites, also known as Simple Sequence Repeats (SSRs), are evolutionarily conserved repeat elements distributed non-randomly in all genomes. Many studies have investigated their pattern of occurrence in order to understand their role, but their identification has largely been non-exhaustive and limited to a few related species or model organisms. Here, we identify ~685 million microsatellites from 719 eukaryotes and analyze their evolutionary trends from protists to mammals. We document novel patterns uniquely demarcating closely related species, including in pathogens like Leishmania as well as in higher organisms such as Drosophila, birds, primates, and cereal crops. The distribution of SSRs in coding and non-coding regions reveals taxon-specific variations in their exonic, intronic and intergenic densities. We also show that specific SSRs accumulate at longer lengths in higher organisms indicating an evolutionary selection pressure. In general, we observe greater constraints in the SSR composition of multicellular organisms with complex cell types, while simpler organisms show more diversity. The conserved microsatellite trends and species-specific signatures identified in this study closely mirror phylogenetic relationships and we hypothesize that SSRs are integral components in speciation and the evolution of organismal complexity. The microsatellite dataset generated in this work provides a large number of candidates for functional analysis and unparalleled scope for understanding their roles across the evolutionary landscape.

2020 ◽  
Vol 65 (2) ◽  
Author(s):  
Arseniy Lobov ◽  
Irina Babkina ◽  
Arina Maltseva ◽  
Natalia Mikhailova ◽  
Andrey Granovitch

The forces driving reproductive isolation emergence during the process of sympatric speciation are still intensely debated. Mechanisms of gametic isolation (which are known to form rapidly in several models) take the central place in these debates. Nevertheless, the approximative capacity of a few investigated models to other taxa could be questioned, generating demand for the adoption of additional model organisms to study sympatric speciation. The group of closely related species of the genus Littorina (subgenus Neritrema) sympatrically inhabiting seashores are promising. In this study, we performed comparative proteomic analysis of penial tissues of four Neritrema species to identify potential effectors contributing to gametic isolation. Among 272 analyzed proteins, 13 mamilliform gland-specific proteins (possibly transferred to the female during copulation) were detected, as well as five proteins specifically expressed in the epithelium of the penial basal part. Eight of these proteins were species-specific and may be involved in the maintenance of reproductive barriers.


2003 ◽  
Vol 39 ◽  
pp. 11-24 ◽  
Author(s):  
Justin V McCarthy

Apoptosis is an evolutionarily conserved process used by multicellular organisms to developmentally regulate cell number or to eliminate cells that are potentially detrimental to the organism. The large diversity of regulators of apoptosis in mammalian cells and their numerous interactions complicate the analysis of their individual functions, particularly in development. The remarkable conservation of apoptotic mechanisms across species has allowed the genetic pathways of apoptosis determined in lower species, such as the nematode Caenorhabditis elegans and the fruitfly Drosophila melanogaster, to act as models for understanding the biology of apoptosis in mammalian cells. Though many components of the apoptotic pathway are conserved between species, the use of additional model organisms has revealed several important differences and supports the use of model organisms in deciphering complex biological processes such as apoptosis.


2019 ◽  
Author(s):  
Andrea Acurio ◽  
Flor T. Rhebergen ◽  
Sarah Paulus ◽  
Virginie Courtier-Orgogozo ◽  
Michael Lang

AbstractBackgroundMale genitals have repeatedly evolved left-right asymmetries, and the causes of such evolution remain unclear. TheDrosophila nannopteragroup contains four species, among which three exhibit left-right asymmetries of distinct genital organs. In the most studied species,Drosophila pachea, males display asymmetric genital lobes and they mate right-sided on top of the female. Copulation position of the other species is unknown.ResultsTo assess whether the evolution of genital asymmetry could be linked to the evolution of one-sided mating, we examined phallus morphology and copulation position inD. pacheaand closely related species. The phallus was found to be symmetric in all investigated species exceptD. pachea, which display an asymmetric phallus with a right-sided gonopore, andD. acanthoptera, which harbor an asymmetrically bent phallus. In all examined species, males were found to position themselves symmetrically on top of the female, except inD. pacheaandD. nannoptera, where males mated right-sided, in distinctive, species-specific positions. In addition, the copulation duration was found to be increased innannopteragroup species compared to closely related outgroup species.ConclusionOur study shows that gains, and possibly losses, of asymmetry in genital morphology and mating position have evolved repeatedly in thenannopteragroup. Current data does not allow us to conclude whether genital asymmetry has evolved in response to changes in mating position, or vice versa.


2020 ◽  
Vol 21 (24) ◽  
pp. 9421
Author(s):  
Lidia Skuza ◽  
Ewa Filip ◽  
Izabela Szućko ◽  
Jan Bocianowski

Secale is a small but very diverse genus from the tribe Triticeae (family Poaceae), which includes annual, perennial, self-pollinating and open-pollinating, cultivated, weedy and wild species of various phenotypes. Despite its high economic importance, classification of this genus, comprising 3–8 species, is inconsistent. This has resulted in significantly reduced progress in the breeding of rye which could be enriched with functional traits derived from wild rye species. Our previous research has suggested the utility of non-coding sequences of chloroplast and mitochondrial DNA in studies on closely related species of the genus Secale. Here we applied the SPInDel (Species Identification by Insertions/Deletions) approach, which targets hypervariable genomic regions containing multiple insertions/deletions (indels) and exhibiting extensive length variability. We analysed a total of 140 and 210 non-coding sequences from cpDNA and mtDNA, respectively. The resulting data highlight regions which may represent useful molecular markers with respect to closely related species of the genus Secale, however, we found the chloroplast genome to be more informative. These molecular markers include non-coding regions of chloroplast DNA: atpB-rbcL and trnT-trnL and non-coding regions of mitochondrial DNA: nad1B-nad1C and rrn5/rrn18. Our results demonstrate the utility of the SPInDel concept for the characterisation of Secale species.


1980 ◽  
Vol 28 (1) ◽  
pp. 103 ◽  
Author(s):  
NA Campbell ◽  
JM Dearn

Morphological variation between and within the closely related species Praxibuius sp.. Kosciuscola cognatus and K. usiratus has been examined along three independent altitudinal transects, by a multivariate statistical approach. The analyses, which were restricted to males. show that there is complete morphological separation between the three species. Moreover. there are species-specific patterns of character correlation which are consistent and relatively invariant within species, and do not exhibit altitudinal variation. The results suggest that there exist both distinct invariant species-specific character patterns and variable character patterns showing intraspecific variation. It is concluded that speciation in these grasshoppers could have involved genetic changes quite distinct from those involved in local intraspecific adaptation. Two further results are: first. evidence has been obtained for character displacement between Kosciuscola cognaius and Praxibulus sp. in an area of extensive sympatry: second. populations of K. cognatus along one transect, with a karyotype intermediate between typical K. cognatus and X usiiatus, show a parallel change in morphology towards that characteristic of K. usiiatus.


Author(s):  
Megan Crow ◽  
Hamsini Suresh ◽  
John Lee ◽  
Jesse Gillis

ABSTRACTWhat makes a mouse a mouse, and not a hamster? The answer lies in the genome, and more specifically, in differences in gene regulation between the two organisms: where and when each gene is expressed. To quantify differences, a typical study will either compare functional genomics data from homologous tissues, limiting the approach to closely related species; or compare gene repertoires, limiting the resolution of the analysis to gross correlations between phenotypes and gene family size. As an alternative, gene coexpression networks provide a basis for studying the evolution of gene regulation without these constraints. By incorporating data from hundreds of independent experiments, meta-analytic coexpression networks reflect the convergent output of species-specific transcriptional regulation.In this work, we develop a measure of regulatory evolution based on gene coexpression. Comparing data from 14 species, we quantify the conservation of coexpression patterns 1) as a function of evolutionary time, 2) across orthology prediction algorithms, and 3) with reference to cell- and tissue-specificity. Strikingly, we uncover deeply conserved patterns of gradient-like expression across cell types from both the animal and plant kingdoms. These results suggest that ancient genes contribute to transcriptional cell identity through mechanisms that are independent of duplication and divergence.


Zootaxa ◽  
2020 ◽  
Vol 4821 (2) ◽  
pp. 250-276
Author(s):  
DMITRI YU. TISHECHKIN

In Russia, Kazakhstan, and Central Asia the genus Anaceratagallia includes 14 species from two subgenera; all species except one belong to the nominotypical subgenus and can be classified into four groups according to the structure of male genitalia. The illustrated descriptions for all species are given, with male calling signal oscillograms provided for nine species. Ten new synonyms are established. Comparative investigation of morphological and acoustic characters of Anaceratagallia species showed that small differences in the structure of male genitalia and 2nd abdominal apodemes are not species-specific traits. All species studied in nature appeared to be polyphagous feeding on different species of herbaceous dicotyledons. It is assumed that closely related species within each group of the subgenus Anaceratagallia arose as a result of allopatric speciation and became secondarily sympatric due to subsequent range expansions.


2008 ◽  
Vol 276 (1654) ◽  
pp. 99-108 ◽  
Author(s):  
James M Newcomb ◽  
Paul S Katz

Closely related species can exhibit different behaviours despite homologous neural substrates. The nudibranch molluscs Tritonia diomedea and Melibe leonina swim differently, yet their nervous systems contain homologous serotonergic neurons. In Tritonia , the dorsal swim interneurons (DSIs) are members of the swim central pattern generator (CPG) and their neurotransmitter serotonin is both necessary and sufficient to elicit a swim motor pattern. Here it is shown that the DSI homologues in Melibe , the cerebral serotonergic posterior-A neurons ( Ce SP-As), are extrinsic to the swim CPG, and that neither the Ce SP-As nor their neurotransmitter serotonin is necessary for swim motor pattern initiation, which occurred when the Ce SP-As were inactive. Furthermore, the serotonin antagonist methysergide blocked the effects of both the serotonin and Ce SP-As but did not prevent the production of a swim motor pattern. However, the Ce SP-As and serotonin could influence the Melibe swim circuit; depolarization of a cerebral serotonergic posterior-A was sufficient to initiate a swim motor pattern and hyperpolarization of a Ce SP-A temporarily halted an ongoing swim motor pattern. Serotonin itself was sufficient to initiate a swim motor pattern or make an ongoing swim motor pattern more regular. Thus, evolution of species-specific behaviour involved alterations in the functions of identified homologous neurons and their neurotransmitter.


2021 ◽  
Vol 3 (2) ◽  
pp. 260-272
Author(s):  
Mukesh Thakar ◽  
Tina Sharma

Disorganized and chaotic collection of the Euphorbia plant species from the wild is one of the major reasons for its endangered status. According to CITES, the trade in Euphorbia royleana species is prohibited under Appendix II. However, the trade continues unabated as current identification methods do not discriminate between closely related species.  In the present study, a DNA barcoding method has been used to establish inter- and intra-specific divergences of both matK and rbcL regions by using pairwise genetic distance measurement methods for evaluating the maximum barcoding gap. The matk and rbcL yielded a 100% amplification and sequencing success rate to distinguish closely related species of Euphorbia royleana unambiguously. The matk and rbcL showed average interspecific genetic distance divergence values of 0.031and 0.015, respectively. The maximum number of species-specific SNPs was observed in matK sequences at seven consecutive sites, which could distinguish Euphorbia royleana from closely related species.  The best candidate barcoding region to identify Euphorbia royleana was found to be matK with a single-locus barcoding approach. Furthermore, the species discrimination method was developed with the help of species-specific SNPs derived from the matK barcoding region to accurately authenticate Euphorbia royleana, and it provided 100% species resolution


eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Gabriela Santos-Rodriguez ◽  
Irina Voineagu ◽  
Robert James Weatheritt

Many primate genes produce circular RNAs (circRNAs). However, the extent of circRNA conservation between closely related species remains unclear. By comparing tissue-specific transcriptomes across over 70 million years of primate evolution, we identify that within 3 million years circRNA expression profiles diverged such that they are more related to species identity than organ type. However, our analysis also revealed a subset of circRNAs with conserved neural expression across tens of millions of years of evolution. By comparing to species-specific circRNAs, we identified that the downstream intron of the conserved circRNAs display a dramatic lengthening during evolution due to the insertion of novel retrotransposons. Our work provides comparative analyses of the mechanisms promoting circRNAs to generate increased transcriptomic complexity in primates.


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