Glossary of terms

Aneuploid or Aneuploidy: A typical human cell contains 46 chromosomes, including X and Y. In some cases, when a cell divides it can have one or more extra or missing chromosome and this is termed aneuploidy.

Array Comparative Genomic Hybridisation (aCGH): A technology that compares the amount of DNA in a sample cell to a known reference. The sample and reference are labelled with different fluorescent dyes, combined, then competitively hybridised to targets on a microarray. The relative amount of fluorescence is then compared to assess the amount of test to reference DNA. 

Bacterial Artificial Chromosomes (BACs): Bacterial DNA constructs containing fragments of human DNA target sequence that are grown in bacterial culture then extracted.

Bacterial Artificial Chromosomes (BAC) array: A microarray with purified BACs spot printed onto the microarray surface. Each spot contains one specific single DNA target that ranges in size from approximately 150 kb in length.

Clinical Pregnancy: A pregnancy indicated by the ultrasound detection of a gestational sac in the uterus.

Degenerate Oligonucleotide Primed (DOP) PCR: DOP-PCR uses primers that can bind to many sequences in order to product a large and diverse range of PCR products.

Euploid or Euploidy: A typical human cell contains 46 chromosomes, including X and Y and this is termed euploidy.

Fluorescent Labelling or Labelling: The process of attaching a fluorescent tag (ie a fluorophore) to DNA.

IVF: In-vitro fertilisation.

Microarray: DNA sequences arranged in a grid pattern attached to a solid surface.

Morphology: The form, structure and shape of an object. This can be applied to cells growing in culture. 

Oligonucleotide array: A microarray where short (60 basepairs) probes are synthesised directly onto the microarray surface.

Polymerase Chain Reaction (PCR): A method for amplifying DNA.

Pre-implantation Genetic Diagnosis (PGD): A technology to screen specific gene disorders or monogenic disease of an embryo prior to transfer into the uterus.

Pre-implantation Genetic Screening (PGS): A technology to screen the chromosomal complement of an embryo prior to transfer into the uterus.

Whole Genome Amplification (WGA): The process which employs PCR to make copies of the whole genome from a small amount of starting DNA.