Genomic architecture of adaptive color pattern divergence and convergence in Heliconius butterflies

Identifying the genetic changes driving adaptive variation in natural populations is key to understanding the origins of biodiversity. The mosaic of mimetic wing patterns in Heliconius butterflies makes an excellent system for exploring adaptive variation using next-generation sequencing. In this study, we use a combination of techniques to annotate the genomic interval modulating red color pattern variation, identify a narrow region responsible for adaptive divergence and convergence in Heliconius wing color patterns, and explore the evolutionary history of these adaptive alleles. We use whole genome resequencing from four hybrid zones between divergent color pattern races of Heliconius erato and two hybrid zones of the co-mimic Heliconius melpomene to examine genetic variation across 2.2 Mb of a partial reference sequence. In the intergenic region near optix, the gene previously shown to be responsible for the complex red pattern variation in Heliconius, population genetic analyses identify a shared 65-kb region of divergence that includes several sites perfectly associated with phenotype within each species. This region likely contains multiple cis-regulatory elements that control discrete expression domains of optix. The parallel signatures of genetic differentiation in H. erato and H. melpomene support a shared genetic architecture between the two distantly related co-mimics; however, phylogenetic analysis suggests mimetic patterns in each species evolved independently. Using a combination of next-generation sequencing analyses, we have refined our understanding of the genetic architecture of wing pattern variation in Heliconius and gained important insights into the evolution of novel adaptive phenotypes in natural populations.

Frequency of Low-level Mosaicism in X-Cromosome in Couples with Antecedent of Recurrent Miscarriages

Recurrent miscarriage occurs in around 1 to 7 percent of couples. The etiology involves genetic, immunologic, anatomic, hormonal, metabolic, thrombophilic and infectious factors. With the aim of establishing the frequency of low-level mosaicism in the X-chromosome, in a population of couples with prior recurrent miscarriages, a prospective case-control cytogenetic study took place on 20 couples, at the biogenetic laboratory in CECOLFES (Colombian Center of Fertility and Sterility). Clinical pathologic evaluation, anatomic, hormonal, infectious, andrologic and genetic studies were performed. As a conventional method in cytogenetic techniques, banding GTG was used for the study of structural and numeric chromosomal abnormalities whereas the molecular method of Fluorescence In Situ Hybridization (FISH) was used to confirm the mosaicism in sexual chromosomes. According to paraclinic results from the participating couples, diagnosis showed immunologic (75%), anatomic (30%), hormonal (25%), male (25%), infectious (25%), genetic (15%) and idiophatic factors (10%). Results from the cytogenetic analysis, were 10% of low-level mosaicism in the X-chromosome in two women whose final diagnosis included genetic and infectious factors for one and genetic and immunologic factors for the other. Only 10 % of the total miscarriages from the couples were evaluated. Conclusions include aspects such as multifactorial evidence of pathogenesis in recurrent miscarriage, the sub-diagnosis of genetic factors and the need to focus future investigations on cytogenetic interpretation and the clinicalpathological association between low-level mosaicism in the X-cromosome and recurrent miscarriage.