Chromosomal Assignment of a Family of Human Oncogenes

A family of human transforming genes, previously shown to share homology with the ras family of viral oncogenes, maps to three different human chromosomes. A well-characterized mouse-human hybrid cell panel, combined with Southern blotting, was used in this study. The transforming gene of the T24 bladder carcinoma cell line maps to human chromosome 11. An oncogene isolated from the lung carcinoma cell line SK-Calu-1 maps to human chromosome 12. The third ras-related gene, cloned from SK-N-SH, a neuroblastoma cell line, maps to human chromosome 1

Phylogenetic Analysis of Kindlins Suggests Subfunctionalization of an Ancestral Unduplicated Kindlin into Three Paralogs in Vertebrates

Kindlin proteins represent a newly discovered family of evolutionarily conserved FERM domain-containing proteins. This family includes three highly conserved proteins: Kindlin-1, Kindlin-2 and Kindlin-3. All three Kindlin proteins are associated with focal adhesions and are involved in integrin activation. The FERM domain of each Kindlin is bipartite and plays a key role in integrin activation. We herein explore for the first time the evolutionary history of these proteins. The phylogeny of the Kindlins suggests a single ancestral Kindlin protein present in even the earliest metazoan ie, hydra. This protein then underwent duplication events in insects and also experienced genome duplication in vertebrates, leading to the Kindlin family. A comparative study of the Kindlin paralogs showed that Kindlin-2 is the slowest evolving protein among the three family members. The analysis of synonymous and non-synonymous substitutions in orthologous Kindlin sequences in different species showed that all three Kindlins have been evolving under the influence of purifying selection. The expression pattern of Kindlins along with phylogenetic studies supports the subfunctionalization model of gene duplication

Evidence for independent Hox gene duplications in the hagfish lineage: a PCR-based gene inventory of Eptatretus stoutii

Hox genes code for transcription factors that play a major role in the development of all animal phyla. In invertebrates these genes usually occur as tightly linked cluster, with a few exceptions where the clusters have been dissolved. Only in vertebrates multiple clusters have been demonstrated which arose by duplication from a single ancestral cluster. This history of Hox cluster duplications, in particular during the early elaboration of the vertebrate body plan, is still poorly understood. In this paper we report the results of a PCR survey on genomic DNA of the pacific hagfish Eptatretus stoutii. Hagfishes are one of two clades of recent jawless fishes that are an offshoot of the early radiation of jawless vertebrates. Our data provide evidence for at least 33 distinct Hox genes in the hagfish genome, which is most compatible with the hypothesis of multiple Hox clusters. The largest number, seven, of distinct homeobox fragments could be assigned to paralog group 9, which could imply that the hagfish has more than four clusters. Quartet mapping reveals that within each paralog group the hagfish sequences are statistically more closely related to gnathostome Hox genes than with either amphioxus or lamprey genes. These results support two assumptions about the history of Hox genes: (1) The association of hagfish homeobox sequences with gnathostome sequences suggests that at least one Hox cluster duplication event happened in the stem of vertebrates, i.e., prior to the most recent common ancestor of jawed and jawless vertebrates. (2) The high number of paralog group 9 sequences in hagfish and the phylogenetic position of hagfish suggests that the hagfish lineage underwent additional independent Hox cluster/-gene duplication events