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Biology subjects

Igic, B.

Publications and source records attributed to Igic, B..

5 recordsLinked to original sources

kakapo: Easy extraction and annotation of genes from raw RNA-seq reads

kakapo (k[a]k[a]p[o]) is a python-based pipeline that allows users to extract and assemble one or more specified genes or gene families. It flexibly uses original RNA-seq read or GenBank SRA accession inputs without performing assembly of entire transcriptomes. The pipeline identifies open reading frames in the assembled gene transcripts and annotates them. It optionally filters raw reads for ribosomal, plastid, and mitochondrial reads, or reads belonging to non-target organisms (e.g., viral, bacterial, human). kakapo can be employed to extract arbitrary loci, such as those commonly used for phylogenetic inference in systematics or candidate genes and gene families in phylogenomic and metagenomic studies. We provide example applications and discuss how its use can offset the declining value of the GenBanks single-gene databases and help assemble datasets for a variety of phylogenetic analyses.

bioinformatics↗

Biosystematic Studies on the Status of Solanum chilense (Dunal) Reiche

AO_SCPLOWBSTRACTC_SCPLOWO_LIMembers of Solanum sect. Lycopersicum are commonly used as a source of exotic germplasm for improvement of the cultivated tomato, and are increasingly employed in basic research. Although it experienced significant early and ongoing work, the taxonomic status of many wild species in this section has undergone a number of significant revisions, and remains uncertain. C_LIO_LIHere, we examine the taxonomic status of obligately outcrossing Chilean wild tomato (Solanum chilense) using reduced-representation sequencing (RAD-seq), a range of phylogenetic and population genetic analyses, crossing data, and morphological data. C_LIO_LIOverall, each of our analyses provides some weight of evidence that the Pacific coastal populations and Andean inland populations of the currently described S. chilense represent separately evolving populations. C_LIO_LIDespite its vast economic importance, Solanum sect. Lycopersicon still exhibits considerable taxonomic instability. A pattern of under-recognition of outcrossing species may be common across flowering plants. We discuss the possible causes and implications of this observation, with a focus on macroevolutionary inference. C_LI

evolutionary biology↗

Ecological Specialization and Diversification in Birds

Ecological specialization is widely thought to influence patterns of species richness by affecting rates at which species multiply and perish. Quantifying specialization is challenging, and using only one or a small number of ecological axes could bias estimates of overall specialization. Here, we calculate an index of specialization, based on seven measured traits, and estimate its effect on speciation and extinction rates in a large clade of birds. We find that speciation rate is independent of specialization, suggesting independence of local ecology and the geographic distributions of populations that promote allopatric species formation. Although some analyses suggest that more specialized species have higher extinction rates, leading to negative net diversification, this relationship is not consistently identified across our analyses. Our results suggest that specialization may drive diversification dynamics only on local scales or in specific clades, but is not generally responsible for macroevolutionary disparity in lineage diversification rates.

evolutionary biology↗

Nectar robbing in the trainbearers (Lesbia, Trochilidae)

Many flower visitors engage in floral larceny, a suite of so-called illegitimate visits in which foragers take nectar without providing pollination services. The data on prevalence of illegitimate visits among hummingbirds, as well as the total proportion of foraging and diet that such visits comprise is broadly lacking. Here, we report the occurrence of nectar larceny in both currently recognized species of trainbearers and analyze the proportion of plant visits categorized by mode of interaction as: primary robbing, secondary robbing, theft, and/or pollination. To the best of our knowledge, we provide the first published report identifying robbing in these species. We augment our original field observations using a trove of data from citizen science databases and literature. Although it is difficult to distinguish primary vs. secondary robbing and theft vs. pollination, we conservatively estimate that ca. 40% of the recorded nectar foraging visits involve nectar robbing. Males appear to engage in robbing marginally more than females, but further studies are necessary to confidently examine the multi-way interactions among sex, species, mode of visitation, and other factors. We discuss the significance of these findings in the context of recent developments in study of nectar foraging, larceny, and pollination from both avian and plant perspectives.

ecology↗

INTERACTION BETWEEN PLOIDY, BREEDING SYSTEM, AND LINEAGE DIVERSIFICATION

If particular traits consistently affect rates of speciation and extinction, broad macroevolutionary patterns can be understood as consequences of selection at high levels of the biological hierarchy. Identifying traits associated with diversification rate differences is complicated by the wide variety of characters under consideration and the statistical challenges of testing for associations from comparative phylogenetic data. Ploidy (diploid vs. polyploid states) and breeding system (self-incompatible vs. self-compatible states) have been repeatedly suggested as possible drivers of differential diversification. We investigate the connections of these traits, including their interaction, to speciation and extinction rates in Solanaceae. We show that the effect of ploidy on diversification can be largely explained by its correlation with breeding system and that additional unknown factors, alongside breeding system, influence diversification rates. These results are largely robust to allowing for diploidization. Finally, we find that the most common evolutionary pathway to polyploidy in Solanaceae occurs via direct breakdown of self-incompatibility by whole genome duplication, rather than indirectly via breakdown followed by polyploidization.

evolutionary biology↗