| restriction fragment length polymorphism | <molecular biology, technique> A method that allows familial relationships to be established by comparing the characteristic polymorphic patterns that are obtained when certain regions of genomic DNA are amplified (typically by PCR) and cut with certain restriction enzymes. The variation in the length of DNA fragments produced by a restriction endonuclease that cuts at a polymorphic locus. Such variations are generated by mutations that create or abolish recognition sites for these enzymes. This is a key tool in DNA fingerprinting, reflecting the existence of different alleles in the individual. Restriction fragment length polymorphism mapping is also used in plant breeding to see if a key trait such as disease resistance is inherited. In principle, an individual can be identified unambiquously by restriction fragment length polymorphism hence the use of restriction fragment length polymorphism in forensic analysis of blood, hair or semen). Similarly, if a polymorphism can be identified close to the locus of a genetic defect, it provides a valuable marker for tracing the inheritance of the defect. Synonym: DNA fingerprinting. Acronym: RFLP (12 Jan 1998) |
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| restriction length polymorphism | Fragment length polymorphism, the existence of allelic forms recognizable by the length of fragments that result when the nucleotide chain is treated by a specific restriction enzyme that cleaves wherever a particular sequence of nucleotides occurs. A mutation in this sequence changes cleaving and hence the number of fragments. (05 Mar 2000) |
| greatest length | Measurement from the cranial to caudal end of the embryo prior to folding. (05 Mar 2000) |
| crown-heel length | Length of an outstretched embryo or foetus from skull vertex to heel. See: Streeter's developmental horizon(s). (05 Mar 2000) |
| crown-rump length | In utero measurement corresponding to the sitting height (crown to rump) of the foetus. Length is considered a more accurate criterion of the age of the foetus than is the weight. The average crown-rump length of the foetus at term is 36 cm. (12 Dec 1998) |
| height-length index | The relation of the height to the length of the skull: (height × 100)/length. Synonym: height-length index, length-height index, transversovertical index. (05 Mar 2000) |
| spinal length | A measurement from the distal surface of the embryo where the plane passes through the developing eye (this is the cranial limit of the spinal cord) down to the rump. (05 Mar 2000) |
| unit of length | Metric system and SI: meter, CGS system: centimeter, variable in the English system: inch for short distances, foot for moderate distances and for elevation, mile for long distances. (05 Mar 2000) |
| leg length inequality | A condition in which one of a pair of legs fails to grow as long as the other. (12 Dec 1998) |
| length | 1. The longest, or longer, dimension of any object, in distinction from breadth or width; extent of anything from end to end; the longest line which can be drawn through a body, parallel to its sides; as, the length of a church, or of a ship; the length of a rope or line. 2. A portion of space or of time considered as measured by its length; often in the plural. "Large lengths of seas and shores." (Shak) "The future but a length behind the past." (Dryden) 3. The quality or state of being long, in space or time; extent; duration; as, some sea birds are remarkable for the length of their wings; he was tired by the length of the sermon, and the length of his walk. 4. A single piece or subdivision of a series, or of a number of long pieces which may be connected together; as, a length of pipe; a length of fence. 5. Detail or amplification; unfolding; continuance as, to pursue a subject to a great length. "May Heaven, great monarch, still augment your bliss. With length of days and every day like this." (Dryden) 6. Distance. "He had marched to the length of Exeter." (Clarendon) at length. At or in the full extent; without abbreviation; as, let the name be inserted at length. At the end or conclusion; after a long period. See Syn. Of At last, under Last. At arm's length. See Arm. Origin: OE. Lengthe, AS. Leng, fr. Land, long, long; akin to D. Lengte, Dan. Laengde, Sw. Langd, Icel. Lengd. See Long. Source: Websters Dictionary (01 Mar 1998) |
| length-breadth index | The ratio of the maximal breadth to the maximal length of the head, obtained by the formula: (breadth × 100)/length. Synonym: length-breadth index. (05 Mar 2000) |
| length-height index | The relation of the height to the length of the skull: (height × 100)/length. Synonym: height-length index, length-height index, transversovertical index. (05 Mar 2000) |
| length of stay | The period of confinement of a patient to a hospital or other health facility. (12 Dec 1998) |
| adolescent round back | Osteochondrosis of the vertebral epiphyses in children. (12 Dec 1998) |
| back | 1. Being at the back or in the rear; distant; remote; as, the back door; back settlements. 2. Being in arrear; overdue; as, back rent. 3. Moving or operating backward; as, back action. Back charges, charges brought forward after an account has been made up. Back filling, the retrograde movement of a man or body of men, without changing front. Back stream, a current running against the main current of a stream; an eddy. To take the back track, to retrace one's steps; to retreat. 1. In human beings, the hinder part of the body, extending from the neck to the end of the spine; in other animals, that part of the body which corresponds most nearly to such part of a human being; as, the back of a horse, fish, or lobster. 2. An extended upper part, as of a mountain or ridge. "[The mountains] their broad bare backs upheave Into the clouds." (Milton) 3. The outward or upper part of a thing, as opposed to the inner or lower part; as, the back of the hand, the back of the foot, the back of a hand rail. "Methought Love pitying me, when he saw this, Gave me your hands, the backs and palms to kiss." (Donne) 4. The part opposed to the front; the hinder or rear part of a thing; as, the back of a book; the back of an army; the back of a chimney. 5. The part opposite to, or most remote from, that which fronts the speaker or actor; or the part out of sight, or not generally seen; as, the back of an island, of a hill, or of a village. 6. The part of a cutting tool on the opposite side from its edge; as, the back of a knife, or of a saw. 7. A support or resource in reserve. "This project Should have a back or second, that might hold, if this should blast in proof." (Shak) 8. The keel and keelson of a ship. 9. <chemical> The upper part of a lode, or the roof of a horizontal underground passage. 10. A garment for the back; hence, clothing. "A bak to walken inne by daylight." (Chaucer) Behind one's back, when one is absent; without one's knowledge; as, to ridicule a person behind his back. Full back, Half back, Quarter back, players stationed behind those in the front line. To be or lie on one's back, to be helpless. To put, or get, one's back up, to assume an attitude of obstinate resistance (from the action of a cat when attacked). To see the back of, to get rid of. To turn the back, to go away; to flee. To turn the back on one, to forsake or neglect him. Origin: As baec, bac; akin to Icel, Sw, & LG. Bak, Dan. Bag; cf. OHG. Bahho ham, Skr. Bhaj to turn, OSlav. Bg flight. Cf. Bacon. Source: Websters Dictionary (01 Mar 1998) |