Biology subjects

Porto-Foresti, F.

Publications and source records attributed to Porto-Foresti, F..

2 recordsLinked to original sources

bioRxiv2024

De novo assembly and characterization of a highly degenerated ZW sex chromosome in the fish Megaleporinus macrocephalus

BackgroundMegaleporinus macrocephalus (piaucu) is a Neotropical fish within Characoidei that presents a well-established heteromorphic ZZ/ZW sex-determination system and thus, constitutes a good model for studying W and Z chromosomes in fishes. We used PacBio reads and Hi-C to assemble a chromosome-level reference genome for M. macrocephalus. We generated family segregation information to construct a genetic map, pool-seq of males and females to characterize its sex system, and RNA-seq to highlight candidate genes of M. macrocephalus sex determination. ResultsM. macrocephalus reference genome is 1,282,030,339 bp in length and has a contig and scaffold N50 of 5.0 Mb and 45.03 Mb, respectively. Based on patterns of recombination suppression, coverage, Fst, and sex-specific SNPs, three major regions were distinguished in the sex chromosome: W-specific (highly differentiated), Z-specific (in degeneration), and PAR. The sex chromosome gene repertoire was composed of genes from the TGF-{beta} family (amhr2, bmp7) and Wnt/{beta}-catenin pathway (wnt4, wnt7a), and some of them were differentially expressed. ConclusionsThe chromosome-level genome of piaucu exhibits high quality, establishing a valuable resource for advancing research within the group. Our discoveries offer insights into the evolutionary dynamics of Z and W sex chromosomes in fish, emphasizing ongoing degenerative processes and indicating complex interactions between Z and W sequences in specific genomic regions. Notably, amhr2 and bmp7 are potential candidate genes for sex determination in M. macrocephalus.

genomics↗

bioRxiv2023

Evolution of ancient satellite DNAs in extant alligators and caimans (Crocodylia, Reptilia)

Crocodilians are one of the oldest extant vertebrate lineages, which exhibits a combination of evolutionary success and morphological resilience that have persisted throughout the history of life on Earth. Such an ability to endure over such a long geological time span is of great evolutionary importance. Here, we performed a comprehensive analysis of the satellite DNA diversity of the extant alligators and caimans, making significant progress in our understanding of the evolution of repetitive regions present in ancient genomes. The alligators and caimans displayed a small number of satDNA families (varying between 3 and 13 satDNAs, in A. sinensis and C. latirostris, respectively) as well as little variation both within and between species, highlighting an exceptional long-term conservation of satDNA elements throughout evolution. We also tracked the origin of the ancestral forms of all satDNAs belonging to the common ancestor of Caimaninae and Alligatoridae. Fluorescence in situ experiments showed distinct hybridization patterns for the identical ortholog satDNAs, indicating their inner dynamic evolution. Why, in addition to their previously known low genetic, karyotype, and morphological diversity, have crocodilians altered so little over such a long period of time with such a highly variable genome fraction? We argued that such an "evolutionary package" was likely the outcome of severe demographic declines or founder events and that it represents evolutionary responses to a long-lasting bottleneck history.

evolutionary biology↗