The human genome holds an extraordinary trove of information about human development, physiology, medicine and evolution. Here we report the results of an international collaboration to produce and make freely available a draft sequence of the human genome. We also present an initial analysis of the data, describing some of the insights that can be gleaned from the sequence.

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Initial sequencing and analysis of the human genome.

http://www.protocol-online.org/forums/index.php?app=core&module=attach&section=attach&attach_id=2894

Studies on transformation of Escherichia coli with plasmids

We have developed a new set of algorithms, collectively called "Velvet," to manipulate de Bruijn graphs for genomic sequence assembly. A de Bruijn graph is a compact representation based on short words (k-mers) that is ideal for high coverage, very short read (25-50 bp) data sets. Applying Velvet to very short reads and paired-ends information only, one can produce contigs of significant length, up to 50-kb N50 length in simulations of prokaryotic data and 3-kb N50 on simulated mammalian BACs. When applied to real Solexa data sets without read pairs, Velvet generated contigs of approximately 8 kb in a prokaryote and 2 kb in a mammalian BAC, in close agreement with our simulated results without read-pair information. Velvet represents a new approach to assembly that can leverage very short reads in combination with read pairs to produce useful assemblies.

https://www.cs.utexas.edu/~tandy/velvet.pdf

Velvet: Algorithms for de novo short read assembly using de Bruijn graphs

We have catalogued the protein kinase complement of the human genome (the "kinome") using public and proprietary genomic, complementary DNA, and expressed sequence tag (EST) sequences. This provides a starting point for comprehensive analysis of protein phosphorylation in normal and disease states, as well as a detailed view of the current state of human genome analysis through a focus on one large gene family. We identify 518 putative protein kinase genes, of which 71 have not previously been reported or described as kinases, and we extend or correct the protein sequences of 56 more kinases. New genes include members of well-studied families as well as previously unidentified families, some of which are conserved in model organisms. Classification and comparison with model organism kinomes identified orthologous groups and highlighted expansions specific to human and other lineages. We also identified 106 protein kinase pseudogenes. Chromosomal mapping revealed several small clusters of kinase genes and revealed that 244 kinases map to disease loci or cancer amplicons.

http://science.sciencemag.org/content/sci/298/5600/1912.full.pdf

The Protein Kinase Complement of the Human Genome

The character of a cell is defined by its constituent proteins, which are the result of specific patterns of gene expression. Crucial determinants of gene expression patterns are DNA-binding transcription factors that choose genes for transcriptional activation or repression by recognizing the sequence of DNA bases in their promoter regions. Interaction of these factors with their cognate sequences triggers a chain of events, often involving changes in the structure of chromatin, that leads to the assembly of an active transcription complex (e.g., Cosma et al. 1999). But the types of transcription factors present in a cell are not alone sufficient to define its spectrum of gene activity, as the transcriptional potential of a genome can become restricted in a stable manner during development. The constraints imposed by developmental history probably account for the very low efficiency of cloning animals from the nuclei of differentiated cells (Rideout et al. 2001; Wakayama and Yanagimachi 2001). A “transcription factors only” model would predict that the gene expression pattern of a differentiated nucleus would be completely reversible upon exposure to a new spectrum of factors. Although many aspects of expression can be reprogrammed in this way (Gurdon 1999), some marks of differentiation are evidently so stable that immersion in an alien cytoplasm cannot erase the memory. The genomic sequence of a differentiated cell is thought to be identical in most cases to that of the zygote from which it is descended (mammalian B and T cells being an obvious exception). This means that the marks of developmental history are unlikely to be caused by widespread somatic mutation. Processes less irrevocable than mutation fall under the umbrella term “epigenetic” mechanisms. A current definition of epigenetics is: “The study of mitotically and/or meiotically heritable changes in gene function that cannot be explained by changes in DNA sequence” (Russo et al. 1996). There are two epigenetic systems that affect animal development and fulfill the criterion of heritability: DNA methylation and the Polycomb-trithorax group (Pc-G/trx) protein complexes. (Histone modification has some attributes of an epigenetic process, but the issue of heritability has yet to be resolved.) This review concerns DNA methylation, focusing on the generation, inheritance, and biological significance of genomic methylation patterns in the development of mammals. Data will be discussed favoring the notion that DNA methylation may only affect genes that are already silenced by other mechanisms in the embryo. Embryonic transcription, on the other hand, may cause the exclusion of the DNA methylation machinery. The heritability of methylation states and the secondary nature of the decision to invite or exclude methylation support the idea that DNA methylation is adapted for a specific cellular memory function in development. Indeed, the possibility will be discussed that DNA methylation and Pc-G/trx may represent alternative systems of epigenetic memory that have been interchanged over evolutionary time. Animal DNA methylation has been the subject of several recent reviews (Bird and Wolffe 1999; Bestor 2000; Hsieh 2000; Costello and Plass 2001; Jones and Takai 2001). For recent reviews of plant and fungal DNA methylation, see Finnegan et al. (2000), Martienssen and Colot (2001), and Matzke et al. (2001).

/pdf/dna-methylation-patterns-and-epigenetic-memory-2xnqjp4ije.pdf

DNA methylation patterns and epigenetic memory

SUMMARY: Phage lysates of a salmonella strain can transduce flagellar characters from that strain to a second strain which absorbs the phage. Non-motile strains treated with lysates o other strains produced stable motile forms detected as spreading swarms in semi-solid agar.
O strains of known species produced swarms with the H antigens characteristic of theirown species, and the species of previously untypable O isolates could be inferred from the H antigens of their induced swarms.
The production of swarms by O strains when treated with lysates of other O strains divided nine Salmonella typhimurium O strains into six interacting groups; there are therefore at least six non-homologous genetic factors, mutation of any of which may cause absence of flagella, thus masking other genes which control H antigenic specificity.
Two flagellated but non-motile strains produced motile forms when treated with lysates of other strains, or of each other. At least two genes concerned with locomotor function are thus recognized. All the motile derivatives of one O strain spread very slowly through semi-solid agar; the ability to spread rapidly could be transduced to them by a second exposure to a lysate.
In exceptional instances two flagellar characters were simultaneously transduced: three O strains sometimes acquired a flagellar antigen from the donor strain at the same time as the H character; another O strain sometimes acquired simultaneously flagellation and the slow-spreading character.
There are therefore many distinct genes controlling the presence, antigenic character and function of the flagella. They may form part of an ordered gene array in which pairs of genes which are sometimes simultaneously transduced by a single phage particle are presumably closely linked.

Transduction of flagellar characters in Salmonella.

I Five years ago, at this Svmposium. E. L. Tatum I , u , L and J. Lederberg first reported some preliminary experiments on genetic recombination in Escherichia coli K-12 (1946). This report will review subsequent developments in this research, with special emphasis on the application of recombination analysis in bacteria to problems of general genetic interest. The standard textbooks of bacteriology have emphasized simple fission to the near exclusion of other modes of bacterial reproduction. This is not surprising in view of the confusing aggregate of conflicting and unconfirmed claims of morphological observations interpreted as sexual processes (reviewed by Bisset, 1950). More authoritative claims of bacterial fusion have appeared (Braun and Elrod, 1946; Stempen and Hutchinson, 19511 but none with the essential \\ concurrence of genetic investigation. On the

Norton D. Zinder

Papers

Transduction of flagellar characters in Salmonella.

Recombination analysis of bacterial heredity.

Functional analysis of bacteriophage f1 intergenic region

Lysogenization and superinfection immunity in Salmonella.

In vitro synthesis of bacteriophage f1 proteins