Genomics Flashcards
Alignment or Mapping
The process of matching reads back to their original position in the reference genome.
Allele
One of a number of alternative forms of the same gene or genetic locus. We inherit one copy of our genetic code from our mother and one copy of our genetic code from our father. Each copy is known as an allele.
Array CGH
Microarray based genomic comparative hybridisation. This is a technique used to detect chromosome imbalances by comparing patient and control DNA and comparing differences between the two sets. It is a useful technique for detecting small chromosome deletions and duplications which would not have been detected with more traditional karyotyping techniques.
Base
A unit of DNA. There are four bases which form the cross links (or rungs) of the DNA double helix: adenine (A), thymine (T), guanine (G) and cytosine (C).
Cell differentiation
The process by which a cell becomes specialized in order to perform a specific function.
Centromere
The point at which the sister chromatids are joined.
Chromosome
A structure located in the nucleus all living cells, comprised of DNA bound around proteins called histones.
Chromosome complement
The normal number of chromosomes in each human cell nucleus is 46 and is composed of 22 pairs of autosomes and a pair of sex chromosomes which determine gender: males have an X and a Y chromosome whilst females have two X chromosomes.
Chromatid
Two identical copies from the replication of a single chromosome. Therefore a sister chromatid refers to either of the two identical copies.
Clinical exome sequencing
Differs per laboratory, but usually involves sequencing of all genes known to be associated with human disease.
Coverage
The number of reads giving information about the base present at a set position in the reference sequence.
Crystallography
The experimental science of determining the arrangement of atoms in crystalline solids.
DNA
Deoxyribonucleic acid. DNA is a molecule consisting of two long chains of nucleotides twisted together to form a double helix. Genes are made from DNA.
DNA sequencing
The process of determining the order of the bases ? adenine, guanine, cytosine and thymine ? in a molecule of DNA.
Epigenome
Chemical marks on the DNA, regulating whether the gene is turned ?on? or ?off?.
Exome
The coding portion of the genes. The exome constitutes 1-2 % of the genome.
Gene
A portion of DNA that serves as the basic unit of heredity.
Genome
The entirety of an individual?s genetic material including ?20 000 genes and the genetic material between genes.
Gene panel
A collection of genes to be sequenced together, which are usually linked by common biological pathways, or known disease associations.
Germline mutations
Where a genetic error occurs in the egg or sperm pre fertilization. Therefore, the genetic mutation is passed onto the offspring.