Biology subjects

Blattner, F. R.

Publications and source records attributed to Blattner, F. R..

4 recordsLinked to original sources

bioRxiv2026

Genomic instability within a sympatric complex of South American garlics (Nothoscordum spp., Amaryllidaceae)

Background and AimsThe evolution of reproductive isolation between previously interbreeding populations is a fundamental driver of plant speciation. Within Amaryllidaceae, Nothoscordum represents an evolutionarily complex genus, characterized by an unusually high incidence of chromosomal rearrangements. During fieldwork, Nothoscordum montevidense and Nothoscordum bonariense were found growing in sympatry, along with individuals exhibiting intermediate morphological traits, suggesting a putative hybrid origin. To test this hypothesis, we employed an integrative approach to characterize the morphologically intermediate specimens and the two sympatric populations. Materials and methodsTo characterize the putative hybrids we have combined morphological, cytogenetic analyses (chromosome counts, CMA/DAPI banding, and FISH) and flow cytometry-based genome size estimation. Phylogenetic relationships and genomic structure were also investigated through Genotyping-by-Sequencing (GBS), complete chloroplast genome assembly, and comparative repetitive DNA analysis. We also performed species distribution modeling and phenological analyses of the putative parental species. Key ResultsMultiple lines of evidence confirm the hybrid origin of the studied plants. Cytogenetic analyses revealed specimens with 2n = 21 (1C {approx} 33 pg = 32.274 Mbp) and 2n = 25 (1C {approx} 37 pg = 36.186 Mbp), accompanied by meiotic irregularities consistent with interspecific hybridization. Chloroplast genome phylogeny identified N. montevidense (2n = 16, 1C {approx} 25 pg) as the maternal lineage, while GBS data confirmed N. bonariense (2n = 26, 1C {approx} 41 pg) as the paternal contributor and revealed evidence of subsequent backcrossing. Comparative analysis of repetitive DNA showed reduced 35S rDNA diversity in the hybrid, indicative of post-hybridization genomic restructuring. Despite the observed genomic complexity, no clear morphological differentiation was detected among hybrid individuals. Phenological analyses and species distribution models demonstrated broad overlap between parental species. ConclusionsOur findings highlight the role of hybridization in shaping genome architecture in cytogenetically labile plant lineages. Furthermore, our results underscore that morphological similarity can mask profound genomic complexity, reinforcing the value of integrative approaches to understand genera characterized by reticulate evolution and genomic instability.

plant biology↗

bioRxiv2025

An area-resolved phylogeography of bulbous barley (Hordeum bulbosum; Poaceae)

Hordeum bulbosum, the closest relative of barley (H. vulgare), is an important source of resistance genes for cereals in the Triticeae. This perennial and mainly outcrossing species occurs with two cytotypes: diploids thrive in the western and central parts of the Mediterranean, while autotetraploids extend from Greece mainly eastwards to western Asia. To elucidate H. bulbosums origin, colonization patterns, population relationships, and distinctions between the two cytotypes, we determined ploidy and performed genotyping-by-sequencing analyses on 314 individuals from across the species distribution range. Our results revealed two distinct lineages within diploid H. bulbosum: individuals from Libya vs. all other diploids. Southeastern Italian populations were the origin for the species expansion eastward into Albania/Greece and westward into mainland Italy, Sicily/Sardinia, Tunisia, and Spain. The tetraploid cytotype originated early in the evolution of the species, thus retaining alleles found in extant Libyan diploids. Tetraploids underwent local introgression from diploids in Greece, where also a secondary origin of tetraploids was detected. We found that ecoclimatic conditions alone cannot account for the clear geographic separation of the cytotypes, as habitats across much of the central Mediterranean would be suitable for both. We conclude that minority cytotype exclusion is the most plausible explanation for the distinct distribution patterns observed. While both cytotypes are morphologically indistinguishable, diploid populations typically occur in scattered stands within their range, while tetraploids tend to form larger, often contiguous populations.

evolutionary biology↗

bioRxiv2019

Genome-wide sequence information reveals recurrent hybridization among diploid wheat wild relatives

Many conflicting hypotheses regarding the relationships among crops and wild species closely related to wheat (the genera Aegilops, Amblyopyrum, and Triticum) have been postulated. The contribution of hybridization to the evolution of these taxa is intensely discussed. To determine possible causes for this, and provide a phylogeny of the diploid taxa based on genome-wide sequence information, independent data was obtained from genotyping-by-sequencing and a target-enrichment experiment that returned 244 low-copy nuclear loci. The data were analyzed with Bayesian, likelihood and coalescent-based methods. D statistics were used to test if incomplete lineage sorting alone or together with hybridization is the source for incongruent gene trees. Here we present the phylogeny of all diploid species of the wheat wild relatives. We hypothesize that most of the wheat-group species were shaped by a primordial homoploid hybrid speciation event involving the ancestral Triticum and Am. muticum lineages to form all other species but Ae. speltoides. This hybridization event was followed by multiple introgressions affecting all taxa but Triticum. Mostly progenitors of the extant species were involved in these processes, while recent interspecific gene flow seems insignificant. The composite nature of many genomes of wheat group taxa results in complicated patterns of diploid contributions when these lineages are involved in polyploid formation, which is, for example, the case in the tetra-and hexaploid wheats. Our analysis provides phylogenetic relationships and a testable hypothesis for the genome compositions in the basic evolutionary units within the wheat group of Triticeae.

evolutionary biology↗

bioRxiv2019

Saffron (Crocus sativus) is an autotriploid that evolved in Attica (Greece) from wild Crocus cartwrightianus

Crocus sativus is the source of saffron, which is made from dried stigmas of the plant. It is a male-sterile triploid that ever since its origin has been propagated vegetatively. The mode of evolution and area of origin of saffron are matters of long-lasting debates. Here we analyzed chloroplast genomes, genotyping-by-sequencing (GBS) data, nuclear single-copy genes, and genome sizes to solve these controversial issues. We could place 99.3% of saffron GBS alleles in Crocus cartwrightianus, a species occurring in southern mainland Greece and on Aegean islands, identifying it as the sole progenitor of saffron. Phylogenetic and population assignment analyses together with chloroplast polymorphisms indicated the wild C. cartwrightianus population south of Athens as most similar to C. sativus. We conclude that the crop is an autotriploid that evolved in Attica by combining two different genotypes of C. cartwrightianus. Vegetative propagation prevented afterwards segregation of the favorable traits of saffron.

evolutionary biology↗