Project description:In this study, we utilized Comparative Genomic Hybridization (CGH), using probes designed from EST sequence, to identify genes located on the X chromosome of four species in the stalk-eyed fly genus Teleopsis. Analysis of log ratio values from the CGH microarrays for over 3400 genes produces a strongly bimodal distribution that clearly differentiates autosomal from X-linked genes for all four species. Genetic mapping of 35 of these genes in T. dalmanni indicates the CGH results correctly identified chromosomal location in all cases. Syntenic comparison with Drosophila indicates that 90% of the X-linked genes in Teleopsis are homologous to genes located on chromosome 2L in D. melanogaster, suggesting the formation of a nearly complete neo-X chromosome from Muller element B in the Dipteran lineage leading to Teleopsis. Overall, this study demonstrates CGH is a useful technique for identifying chromosomal sex-linkage and should be applicable to other organisms with EST or partial genomic information.
Project description:In this study, we utilized Comparative Genomic Hybridization (CGH), using probes designed from EST sequence, to identify genes located on the X chromosome of four species in the stalk-eyed fly genus Teleopsis. Analysis of log ratio values from the CGH microarrays for over 3400 genes produces a strongly bimodal distribution that clearly differentiates autosomal from X-linked genes for all four species. Genetic mapping of 35 of these genes in T. dalmanni indicates the CGH results correctly identified chromosomal location in all cases. Syntenic comparison with Drosophila indicates that 90% of the X-linked genes in Teleopsis are homologous to genes located on chromosome 2L in D. melanogaster, suggesting the formation of a nearly complete neo-X chromosome from Muller element B in the Dipteran lineage leading to Teleopsis. Overall, this study demonstrates CGH is a useful technique for identifying chromosomal sex-linkage and should be applicable to other organisms with EST or partial genomic information. Two-condition experiment, female vs. male DNA, for four species, each with 4 biological replicates
Project description:We utilized Comparative Genomic Hybridization (CGH), using probes designed from de novo assembly of 10 tissues into a grand transcriptome to identify genes located on the X and Y chromosomes of a stalk-eyed fly, Teleopsis dalmanni. We use next generation sequencing of RNA to identify over 500 genes that are differentially expressed in the testes due to the effects of a driving X chromosome (XSR) in T. dalmanni. Most of these genes were X-linked, evolving more rapidly than control genes, and exhibit elevated expression in the gonads. Finally, XSR has become genetically differentiated from standard X chromosomes – using the RNA sequence data, we found nearly 1000 sites in X-linked genes and only a handful in autosomal genes where there was a fixed nucleotide difference. We conclude that XSR has led to widespread sequence and expression divergence on the X chromosome in T. dalmanni.
Project description:We utilized Comparative Genomic Hybridization (CGH), using probes designed from de novo assembly of 10 tissues into a grand transcriptome to identify genes located on the X and Y chromosomes of a stalk-eyed fly, Teleopsis dalmanni. We use next generation sequencing of RNA to identify over 500 genes that are differentially expressed in the testes due to the effects of a driving X chromosome (XSR) in T. dalmanni. Most of these genes were X-linked, evolving more rapidly than control genes, and exhibit elevated expression in the gonads. Finally, XSR has become genetically differentiated from standard X chromosomes M-bM-^@M-^S using the RNA sequence data, we found nearly 1000 sites in X-linked genes and only a handful in autosomal genes where there was a fixed nucleotide difference. We conclude that XSR has led to widespread sequence and expression divergence on the X chromosome in T. dalmanni. Two-condition experiment, female vs. male DNA, for one species with 4 biological replicates
