Mitochondrial genome

The mitochondrial genome is the genetic material of the mitochondria. The mitochondria are organelles that reproduce themselves semi-autonomously within eukaryotic cells.

The genetic material forming the mitochondrial genome is similar in structure to that of the prokaryotic genetic material. The mitochondrial chromosome is a circular DNA molecule, but unlike prokaryotes it is much smaller and several copies are present. This similarity supports the hypothesis that mitochondria arose from intracellular bacterial symbiotes, i.e. the endosymbiotic theory.

The mitochondria of a sexually-reproducing species are inherited maternally. In this way, mitochondrial genetic diseases can affect both males and females, but can only be transmitted by females to their offspring. The human mitochondrial genome consists of 16,569 base pairs, which encodes only 13 proteins, 22 tRNAs, and 2 rRNAs.

Compared to the nuclear genome, the mitochondrial genome possesses some very interesting features:

• All the genes are carried on a single circular DNA molecule.
• The genetic material is not bounded by a nuclear envelope.
• The DNA is not packed into chromatin.
• The genome contains little non-coding DNA ("junk" DNA, or introns).
• Some codons do not follow the universal rules in translation. Instead they resemble those of purple non-sulfur bacteria.
• Some bases are considered part of two different genes: both as the last base of one gene and as the first base of the next gene.

http://en.wikipedia.org/wiki/Mitochondrial_genome

Genome

In biology the genome of an organism is its whole hereditary information and is encoded in the DNA (or, for some viruses, RNA). This includes both the genes and the non-coding sequences of the DNA. The term was coined in 1920 by Hans Winkler, Professor of Botany at the University of Hamburg, Germany, as a portmanteau of the words gene and chromosome.^[1]

More precisely, the genome of an organism is a complete DNA sequence of one set of chromosomes; for example, one of the two sets that a diploid individual carries in every somatic cell. The term genome can be applied specifically to mean the complete set of nuclear DNA (i.e., the "nuclear genome") but can also be applied to organelles that contain their own DNA, as with the mitochondrial genome or the chloroplast genome. When people say that the genome of a sexually reproducing species has been "sequenced," typically they are referring to a determination of the sequences of one set of autosomes and one of each type of sex chromosome, which together represent both of the possible sexes. Even in species that exist in only one sex, what is described as "a genome sequence" may be a composite from the chromosomes of various individuals. In general use, the phrase "genetic makeup" is sometimes used conversationally to mean the genome of a particular individual or organism. The study of the global properties of genomes of related organisms is usually referred to as genomics, which distinguishes it from genetics which generally studies the properties of single genes or groups of genes.

Both the number of base pairs and the number of genes vary widely from one species to another, and there is little connection between the two. At present, the highest known number of genes is around 60,000, for the protozoan causing trichomoniasis (see List of sequenced eukaryotic genomes), almost three times as many as in the human genome.

An analogy to the human genome is that of a book:

• The book is over one billion words long.
• The book is bound in 5,000 300 page volumes.
• The book fits into a cell nucleus the size of a pinpoint.
• A copy of the book (all 5000 volumes) is contained in every cell (except red blood cells) as a strand of DNA over two metres in length.

http://en.wikipedia.org/wiki/Genome

LG 32LB75 Review

LG's 32LB75 forms part of the Korean manufacturers 'Design Art' range of LCD TV's and without a doubt this screen demands to be noticed. If your tastes are conservative this LG may not be for you, but here at HDTVorg we loved the looks. Leaving behind the clunkiness of old LG's the LB75's arced bottom, glossy finish and dark red barrel (connecting the screen to its stand) produce a rather chic piece of kit.

Picture processing technology on the 32LB75 comes in the shape of LG's proprietary XD engine. The XD Engine brings together a range of picture processing enhancements under the XD umbrella, with particular emphasis on improving the input signal quality.

The good news is that the 32LB75 has made great strides for LG with its SD performance. Most notable is the lack of video noise which has plagued LG's of old. Pictures are much sharper and more detailed and perhaps most impressive this is now an LG able to cope with fast moving pictures. Gone is the intrusiveness of motion blurring even in the most demanding situations. The SD performance of LG's 32LB75 is not flawless, but it is enough to place it into a leading pack of LCD TV's in this respect.

http://hdtvorg.co.uk/news/articles/2007123002.htm