Biology subjects

Calderon, L.

Publications and source records attributed to Calderon, L..

3 recordsLinked to original sources

bioRxiv2020

Clonal propagation history shapes the intra-cultivar genetic diversity in Malbec grapevines

Grapevine (Vitis vinifera L.) cultivars are clonally propagated to preserve their varietal attributes. However, novel genetic variation still accumulates due to somatic mutations. Aiming to study the potential impact of clonal propagation history on grapevines intra-cultivar genetic diversity, we have focused on Malbec. This cultivar is appreciated for red wines elaboration, it was originated in Southwestern France and introduced into Argentina during the 1850s. Here, we generated whole-genome resequencing data for four Malbec clones with different historical backgrounds. A stringent variant calling procedure was established to identify reliable clonal polymorphisms, additionally corroborated by Sanger sequencing. This analysis retrieved 941 single nucleotide variants (SNVs), occurring among the analyzed clones. Based on a set of validated SNVs, a genotyping experiment was custom-designed to survey Malbec genetic diversity. We successfully genotyped 214 samples and identified 14 different clonal genotypes, that clustered into two genetically divergent groups. Group-Ar was driven by clones with a long history of clonal propagation in Argentina, while Group-Fr was driven by clones that have longer remained in Europe. Findings show the ability of such approaches for clonal genotypes identification in grapevines. In particular, we provide evidence on how human actions may have shaped Malbec extant genetic diversity pattern.

genomics↗

bioRxiv2020

Genomic structural variation in Nebbiolo grapevines at the individual, clonal and cultivar levels

Structural Variants (SVs) are a widely unexplored source of genetic variation, both due to methodological limitations and because they are generally associated to deleterious effects. However, with the advent of long-range genomic platforms, it has become easier to directly detect SVs. In the same direction, clonally propagated crops provide a unique opportunity to study SVs, offering a suitable genomic environment for their accumulation in heterozygosis. In particular, it has been reported that SVs generate drastic levels of heterozygosity in grapevines. Nebbiolo (Vitis vinifera L.) is a grapevine cultivar typical of north-western Italy, appreciated for its use in producing high-quality red wines. Here, we aimed to analyze the frequency of SVs in Nebbiolo, at three different organizational levels. For this purpose, we generated genomic data based on long-reads, linked-reads and optical mapping. We assembled a reference genome for this cultivar and compared two different clones, including V. vinifera reference genome (PN40024) in our comparisons. Our results indicate that SVs differentially occurring between Nebbiolo clones might be rare, while SVs differentiating haplotypes of the same individual are as abundant as those that occur differentially between cultivars.

genomics↗

bioRxiv2020

Partial rescue of neuronal genes deregulated in Cornelia de Lange Syndrome by cohesin

Cornelia de Lange Syndrome (CdLS) is a human developmental disorder caused by mutations that compromise the function of cohesin, a major regulator of 3D genome organization. Cognitive impairment is a universal and as yet unexplained feature of CdLS. We characterized the transcriptional profile of cortical neurons from CdLS patients and found deregulation of hundreds of genes enriched for neuronal functions related to synaptic transmission, signalling processes, learning and behaviour. Inducible proteolytic cleavage of cohesin disrupted 3-D genome organization and transcriptional control in post-mitotic cortical mouse neurons. The genes affected belonged to similar gene ontology classes and showed significant numerical overlap with those deregulated in CdLS. Interestingly, gene expression was largely rescued by subsequent reconstitution of cohesin function. These experiments show that cohesin is continuously required for neuronal gene expression and provide a tractable approach for addressing mechanisms of neuronal dysfunction in CdLS.

cell biology↗