Human genes: number

Roest Croellius H et al. Estimate of human gene number provided by genomewide analysis using Tetradon nigroviridis DNA sequence. Nature Genet 2000 25 235-238. 

Many important findings have already emerged. The one to date that has generated the most discussion is that the number of human genes may be only two to three times that estimated for the roundworm and the fruit fly. 

Potentially, interferon is an ideal anhviral agent in that it acts on many different vimses and is not toxic to host cells. However, the exploitation of this agent in the treatment of viral infechons has been delayed by a number of factors. For example, it has proved to be species-specific and interferons raised in animal sources offered little protechon to human cells. Human interferon is thus needed for the treatment of human infechons and the produehon and purificahon of human interferon on a large scale has proved difficult. The inserhon of human genes for interferon into E. coli has resolved the produehon problems (Chapter 24). Clinical trials have demonstrated that interferon prevents rhinovirus infeehon and has a beneficial effect in herpes, cytomegalovims and hepahtis B vims infechons. 

In 1993/1994 a series of publications caused a stir in the AD research community, since for the first time they linked a specific neuropathological process in late-onset AD to a genetic marker. Researchers looking at the composition of plaques found that the protein apolipoprotein E (ApoE) was associated with p-amyloid in the cerebrospinal fluid (CSF) of AD patients (Strittmatter et al., 1993). The gene for ApoE is on the same human chromosome (number 19) which was a risk factor in some AD pedigrees. The gene for ApoE comes in three versions (alleles) Apo s2, Apo s3 and, most importantly, Apo s4 these result in three slightly different variants of the protein. Humans carry two versions of the allele and so can have none, one or two of any of the versions of the Apo... 

Claverie JM. Gene number. What if there are only 30,000 human genes Science 2001 291[5507] 1255-1257. 

HSA is a 585 amino acid, 65.5 kDa polypeptide. It is one of the few plasma proteins that are unglycosylated. A prominent feature is the presence of 17 disulfide bonds, which help stabilize the molecule s three-dimensional structure. HSA is synthesized and secreted from the liver, and its gene is present on human chromosome number 4. 

Mutations associated with inheritable diseases are numbered in MIM notation as described in McKusick, V. A. Mendelian Inheritance in Man. A Catalog of Human Genes and Genetic Disorders, 12th edn. Baltimore Johns Hopkins University Press, 1998. An updated Internet version is found at Online Mendelian Inheritance in Man, OMIM . McKusick-Nathans Institute for Genetic Medicine, Johns Hopkins University (Baltimore, MD) and National Center for Biotechnology Information, National Library of Medicine (Bethesda, MD), 2000, www.ncbi.nlm.nih.gov/ omim/. 

The phenomenon of imprinting refers to the fact that a small number of human genes are transcriptionally active only when transmitted by one of the two sexes. A good example is provided by Prader-Willi syndrome, a disorder characterized by moderate mental retardation, hypogonadism, small hands and feet, and obesity. Most cases of Prader-Willi syndrome are caused by a deletion of 4 million bases (4 megabases or Mb) on the long arm of chromosome 15. However, the deletion produces this syndrome only if it is transmitted by the fether. If the same deletion is... 

Following the sequencing of the human genome it was found that there were between 30 000 and 40 000 genes that code for proteins, only twice as many as occur in the fruit fly or the nematode worm However, it does appear that human genes are more complex than those of flies and worms in that they generate a large number of proteins due to the alternative ways... 

The Affymetrix U95A GeneChip containing 12,500 known human genes was used for this purpose. Two adjacent breast tumors from an 87-year old woman were removed and used in the study along with an additional five breast tumors obtained from different individuals. Thus, seemingly related tumors from one individual could be compared with tumors from different sources to validate the microarray-based prognosis. In addition to validation of the microarray for this purpose, the researchers examined a number of... 

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