Biomedical subjects

José M Ranz

Publications and source records attributed to José M Ranz.

4 recordsLinked to original sources

PubMed2005

Uncovering evolutionary patterns of gene expression using microarrays.

The advent of microarray technology is providing new insights into fundamental questions in evolutionary biology. Here, we review the recent literature on the use of microarrays to study the evolution of genome-wide patterns of gene expression within and between species. Large levels of variation in gene expression patterns have been observed at the intra and interspecific level, and a substantial fraction of transcriptional variation has a genetic component that is contributed by changes in both cis-acting and trans-acting regulatory elements. We argue that there is solid evidence to show that the temporal dynamics of transcriptional variation is largely determined by natural selection, with the fraction of the transcriptome more closely related to sex and reproduction evolving more rapidly.

Animals↗

PubMed2004

Anomalies in the expression profile of interspecific hybrids of Drosophila melanogaster and Drosophila simulans.

When females of Drosophila melanogaster and males of Drosophila simulans are mated, the male progeny are inviable, whereas the female progeny display manifold malformations and are sterile. These abnormalities result from genetic incompatibilities accumulated since the time the lineages of the species diverged, and may have their origin in aberrant gene transcription. Because compensatory changes within species may obscure differences at the regulatory level in conventional comparisons of the expression profile between species, we have compared the gene-expression profile of hybrid females with those of females of the parental species in order to identify regulatory incompatibilities. In the hybrid females, we find abnormal levels of messenger RNA for a large fraction of the Drosophila transcriptome. These include a gross underexpression of genes preferentially expressed in females, accompanying gonadal atrophy. The hybrid females also show significant overexpression of male-biased genes, which we attribute to incompatibilities in the regulatory mechanisms that normally act to control the expression of these genes in females. The net result of the multiple incompatibilities is that the gene-expression profiles of the parental females are more similar to each other than either is to that of the hybrid.

Animals↗

PubMed2003

Rapid evolution of male-biased gene expression in Drosophila.

A number of genes associated with sexual traits and reproduction evolve at the sequence level faster than the majority of genes coding for non-sex-related traits. Whole genome analyses allow this observation to be extended beyond the limited set of genes that have been studied thus far. We use cDNA microarrays to demonstrate that this pattern holds in Drosophila for the phenotype of gene expression as well, but in one sex only. Genes that are male-biased in their expression show more variation in relative expression levels between conspecific populations and two closely related species than do female-biased genes or genes with sexually monomorphic expression patterns. Additionally, elevated ratios of interspecific expression divergence to intraspecific expression variation among male-biased genes suggest that differences in rates of evolution may be due in part to natural selection. This finding has implications for our understanding of the importance of sexual dimorphism for speciation and rates of phenotypic evolution.

Animals↗

PubMed2003

Sex-dependent gene expression and evolution of the Drosophila transcriptome.

Comparison of the gene-expression profiles between adults of Drosophila melanogaster and Drosophila simulans has uncovered the evolution of genes that exhibit sex-dependent regulation. Approximately half the genes showed differences in expression between the species, and among these, approximately 83% involved a gain, loss, increase, decrease, or reversal of sex-biased expression. Most of the interspecific differences in messenger RNA abundance affect male-biased genes. Genes that differ in expression between the species showed functional clustering only if they were sex-biased. Our results suggest that sex-dependent selection may drive changes in expression of many of the most rapidly evolving genes in the Drosophila transcriptome.

Animals↗