Expressed sequence tagIn genetics, an expressed sequence tag (EST) is a short sub-sequence of a cDNA sequence. ESTs may be used to identify gene transcripts, and were instrumental in gene discovery and in gene-sequence determination. The identification of ESTs has proceeded rapidly, with approximately 74.2 million ESTs now available in public databases (e.g. GenBank 1 January 2013, all species). EST approaches have largely been superseded by whole genome and transcriptome sequencing and metagenome sequencing.
Usher syndromeUsher syndrome, also known as Hallgren syndrome, Usher–Hallgren syndrome, retinitis pigmentosa–dysacusis syndrome or dystrophia retinae dysacusis syndrome, is a rare genetic disorder caused by a mutation in any one of at least 11 genes resulting in a combination of hearing loss and visual impairment. It is a major cause of deafblindness and is at present incurable. Usher syndrome is classed into three subtypes (I, II and III) according to the genes responsible and the onset of deafness.
Transgenerational epigenetic inheritanceTransgenerational epigenetic inheritance is the transmission of epigenetic markers and modifications from one generation to multiple subsequent generations without altering the primary structure of DNA. Thus, the regulation of genes via epigenetic mechanisms can be heritable; the amount of transcripts and proteins produced can be altered by inherited epigenetic changes. In order for epigenetic marks to be heritable, however, they must occur in the gametes in animals, but since plants lack a definitive germline and can propagate, epigenetic marks in any tissue can be heritable.
Chromosome 3Chromosome 3 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 3 spans 201 million base pairs (the building material of DNA) and represents about 6.5 percent of the total DNA in cells. The following are some of the gene count estimates of human chromosome 3. Because researchers use different approaches to genome annotation their predictions of the number of genes on each chromosome varies (for technical details, see gene prediction).
Chromosome 4Chromosome 4 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 4 spans more than 193 million base pairs (the building material of DNA) and represents between 6 and 6.5 percent of the total DNA in cells. The chromosome is ~193 megabases in length. In a 2012 paper, 775 protein-encoding genes were identified on this chromosome. 211 (27.9%) of these coding sequences did not have any experimental evidence at the protein level, in 2012.
Chromosome 7Chromosome 7 is one of the 23 pairs of chromosomes in humans, who normally have two copies of this chromosome. Chromosome 7 spans about 160 million base pairs (the building material of DNA) and represents between 5 and 5.5 percent of the total DNA in cells. The following are some of the gene count estimates of human chromosome 7. Because researchers use different approaches to genome annotation their predictions of the number of genes on each chromosome varies (for technical details, see gene prediction).
Chromosome 8Chromosome 8 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 8 spans about 146 million base pairs (the building material of DNA) and represents between 4.5 and 5.0% of the total DNA in cells. About 8% of its genes are involved in brain development and function, and about 16% are involved in cancer. A unique feature of 8p is a region of about 15 megabases that appears to have a high mutation rate.
Chromosome 14Chromosome 14 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 14 spans about 101 million base pairs (the building material of DNA) and represents between 3 and 3.5% of the total DNA in cells. The centromere of chromosome 14 is positioned approximately at position 17.2 Mbp. The following are some of the gene count estimates of human chromosome 14. Because researchers use different approaches to genome annotation their predictions of the number of genes on each chromosome varies (for technical details, see gene prediction).
Chromosome 16Chromosome 16 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 16 spans about 96 million base pairs (the building material of DNA) and represents just under 3% of the total DNA in cells. The following are some of the gene count estimates of human chromosome 16. Because researchers use different approaches to genome annotation their predictions of the number of genes on each chromosome varies (for technical details, see gene prediction).
Overlapping geneAn overlapping gene (or OLG) is a gene whose expressible nucleotide sequence partially overlaps with the expressible nucleotide sequence of another gene. In this way, a nucleotide sequence may make a contribution to the function of one or more gene products. Overlapping genes are present and a fundamental feature of both cellular and viral genomes. The current definition of an overlapping gene varies significantly between eukaryotes, prokaryotes, and viruses.