Project description:<p>Developmental disabilities are birth defects that cause lifelong problems with how a body part or system works. Developmental disabilities include nervous system insults affecting how the brain, spinal cord and nervous system function; they cause intellectual disability, including Down syndrome and fragile X syndrome; and they also cause learning and behavioral disorders, such as autism spectrum disorders. At the Kennedy Krieger Institute, approximately 450 inpatients and 13,000 outpatients are seen per year (involving 114,000 visits). For most of these disorders, the underlying molecular cause has not been identified. Some, such as chromosomal disorders, have a strongly genetic basis while others, such as traumatic brain injury, are caused by environmental insults but are nonetheless influenced by the genetic background. The purpose of the present study is to identify chromosomal abnormalities underlying a variety of developmental disabilities. The approach is to obtain blood and saliva from children, and from one or both biological parents (and in some cases from siblings and/or additional relatives). Genomic DNA is purified and assayed on single nucleotide polymorphism (SNP) microarrays and/or by sequencing, including whole genome sequencing. These technologies provide high resolution information about chromosomal changes, and the information provided by the parental (and other relatives') DNA allows an interpretation of whether changes in a child are inherited or occur <i>de novo</i>. The study design includes multiple data analysis procedures to interpret the biological significance of findings of chromosomal changes relative to a child's parents, relative to children with similar diagnoses, relative to children with other chromosomal anomalies, and (in some cases) relative to the chromosomal status of siblings. We will further interpret the significance of the findings relative to the general (apparently normal) population by obtaining publicly available data from apparently normal individuals. </p>
Project description:Seahorses, pipefishes, and seadragons are fishes from the family Syngnathidae that have evolved extraordinary traits including male pregnancy, elongated snouts, loss of teeth, and dermal bony armor. The developmental genetic and cellular changes that led to the evolution of these traits are largely unknown. Recent syngnathid genomes revealed suggestive gene content differences and provide the opportunity for detailed genetic analyses. We created a single cell RNA sequencing atlas of Gulf pipefish embryos to understand the developmental basis of four traits: derived head shape, toothlessness, dermal armor, and male pregnancy. We completed marker gene analyses, built genetic networks, and examined spatial expression of select genes. We identified osteochondrogenic mesenchymal cells in the elongating face that express regulatory genes bmp4, sfrp1a, and prdm16. We found no evidence for tooth primordia cells, and we observed re-deployment of osteoblast genetic networks in developing dermal armor. Finally, we found that epidermal cells expressed nutrient processing and environmental sensing genes, potentially relevant for the brooding environment. The examined pipefish evolutionary innovations are composed of recognizable cell types, suggesting derived features originate from changes within existing gene networks. Future work addressing syngnathid gene networks across multiple stages and species is essential for understanding how their novelties evolved.