MZ Twins Monozygotic/ identical twins, formed when an early embryo splits in two.
Neurotransmitter A chemical produced by one brain cell that acts on another brain cell to alter its behaviour.
Nucleosome Combination of eight specific histone molecules with DNA wrapped around them.
Phenotype The observable characteristics or traits of an organism.
Pluripotency The ability of a cell to give rise to most other cell types. Typically, pluripotent mammalian cells give rise to all cells of the body, but not the cells of the placenta.
Priomordial germ cells Very specialised cells created in early development, which give rise ultimately to the gametes.
Promoter Region in front of a gene that controls how a gene is switched on.
Pronucleus The nucleus of a sperm or egg, following entry of a sperm into an egg, but before the two nuclei fuse.
Retrotransposons Unusual segments of DNA that don’t code for protein and can move between different locations in the genome. Believed to have originated from viruses.
RNA Single stranded copy of a specific region of DNA. The term RNA stands for ribonucleic acid. It includes various different classes of RNA molecules including miRNA, mRNA and ncRNA.
Sex chromosomes The X and Y chromosomes that govern sex determination in mammals. Normally, females have two X chromosomes and males have one X and one Y chromosome.
Somatic cells Cells of the body.
Somatic Cell Nuclear Transfer (SCNT) The transfer of the nucleus from a mature cell into another cell, usually an egg.
Somatic mutations Mutations that happen in the cells of the body, rather than ones that have been inherited via sperm or eggs.
Stochastic variation A random change or fluctuation.
Totipotency The ability of a cell to give rise to all cells of the body and the placenta.
Transcription Copying DNA to create RNA molecules.
Transgenerational inheritance The phenomenon in which phenotypic changes in one generation are passed on to the next, without any alteration in the genetic code.
Uniparental disomy A situation where both members of a pair of chromosomes have been inherited from one parent, rather than one from each parent. For example, maternal uniparental disomy of chromosome 11 would mean both copies of chromosome 11 had come from the mother.
Vernalisation The process where plants need a period of cold before they will flower.
Zygote The totipotent cell formed when an egg and a sperm fuse.