1. The process with which foreign DNA that has been introduced into a prokaryotic cell becomes ineffective. 2. A limitation.
- asymmetric fetal growth r. normal fetal head size as a result of preferential shunting of blood to brain, and decreased abdominal circumference from decreased adipose tissue and liver size; probably caused by placental insufficiency.
- fetal growth r. fetal weight ≤5th percentile for gestational age. SYN: intrauterine growth retardation.
- lactase r. an inherited trait in which there is low lactase activity and thus there is defective lactose intestinal metabolism. Cf.:lactase persistence.
- MHC r. T helper cells only recognize an antigen that is presented with class II major histocompatibility antigens whereas T cytotoxic cells usually only recognize a processed antigen in conjunction with class I major histocompatibility antigens.
- symmetric fetal growth r. proportional reduction in fetal head and body size, commonly constitutional or caused by an early intrauterine insult such as infection.
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re·stric·tion ri-'strik-shən n, often attrib the breaking of double-stranded DNA into fragments by restriction enzymes <\restriction sites>
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re·stric·tion (re-strikґshən) 1. a limitation. 2. a thing or process that limits.Medical dictionary. 2011.