Palindrome

views updated May 11 2018

Palindrome

In genetics, the term palindrome refers to a sequence of nucleotides along a DNA (deoxyribonucleic acid) or RNA (ribonucleic acid) strand that contains the same series of nitrogenous bases regardless from which direction the strand is analyzed. Akin to a language palindromewherein a word or phrase is spelled the same left-to-right as right-to-left (e.g., the word RADAR or the phrase able was I ere I saw elba)with genetic palindromes it does not matter whether the nucleic acid strand is read starting from the 3 (three prime) end or the 5 (five prime) end of the strand.

Recent research on palindromes centers on understanding palindrome formation during gene amplification. Other studies have attempted to relate palindrome formation to molecular mechanisms involved in double stranded breaks and in the formation of inverted repeats. Assisted by high speed computers, other groups of scientists link palindrome formation to the conservation of genetic information.

Related to the direction of transcription by RNA polymerase, DNA strands have upstream and downstream terminus defined by differing chemical groups at each end. The ends of each strand of DNA or RNA are termed the 5 (phosphate bound to the 5 position carbon) and 3 (phosphate bound to the 3 carbon) ends to indicate a polarity within the molecule. Using the letters A, T, C, G, to represent the nitrogenous bases adenine, thymine, cytosine, and guanine found in DNA, and the letters A, U, C, G to represent the nitrogenous bases adenine, uracil, cytosine, guanine found in RNA (Note that uracil in RNA replaces the thymine found in DNA), geneticists usually represent DNA by a series of base codes (e.g., 5 AATCGGATTGCA 3). The base codes are usually arranged from the 5 end to the 3 end.

Because of specific base pairing in DNA (i.e., adenine (A) always bonds with (thymine (T) and cytosine (C) always bonds with guanine (G)) the complimentary stand to the sequence 5 AATCGGATTGCA 3 would be 3 TTAGCCTAACGT 5.

With palindromes the sequences on the complimentary strands read the same in either direction. For example, a sequence of 5 GAATTC3 on one strand would be complimented by a 3 CTTAAG 5 strand. In either case, when either strand is read from the 5 prime end the sequence is GAATTC. Another example of a palindrome would be the sequence 5 CGAAGC 3 that, when reversed, still reads CGAAGC.

Palindromes are important sequences within nucleic acids. Often they are the site of binding for specific enzymes (e.g., restriction endobucleases) designed to cut the DNA strands at specific locations (i.e., at palindromes).

Palindromes may arise from brakeage and chromosomal inversions that form inverted repeats that compliment each other. When a palindrome results from an inversion, it is often referred to as an inverted repeat. For example, the sequence 5 CGAAGC 3, if inverted (reversed 180°), still reads CGAAGC.

See also Amino acid; Deoxyribonucleic acid (DNA); DNA replication; DNA synthesis; DNA technology; Gene mutation; Gene splicing; Mutagenesis.

Palindrome

views updated May 21 2018

Palindrome

In genetics , the term palindrome refers to a sequence of nucleotides along a DNA (deoxyribonucleic acid) or RNA (ribonucleic acid) strand that contains the same series of nitrogenous bases regardless from which direction the strand is analyzed. Akin to a language palindrome—wherein a word or phrase is spelled the same left-to-right as right-to-left (e.g., the word RADAR or the phrase "able was I ere I saw elba")—with genetic palindromes it does not matter whether the nucleic acid strand is read starting from the 3' (three prime) end or the 5' (five prime) end of the strand.

Recent research on palindromes centers on understanding palindrome formation during gene amplification. Other studies have attempted to relate palindrome formation to molecular mechanisms involved in double stranded breaks and in the formation of inverted repeats. Assisted by high speed computers, other groups of scientists link palindrome formation to the conservation of genetic information.

Related to the direction of transcription by RNA polymerase, DNA strands have upstream and downstream terminus defined by differing chemical groups at each end. The ends of each strand of DNA or RNA are termed the 5' (phosphate bound to the 5' position carbon ) and 3' (phosphate bound to the 3' carbon) ends to indicate a polarity within the molecule . Using the letters A, T, C, G, to represent the nitrogenous bases adenine, thymine, cytosine, and guanine found in DNA, and the letters A, U, C, G to represent the nitrogenous bases adenine, uracil, cytosine, guanine found in RNA (Note that uracil in RNA replaces the thymine found in DNA), geneticists usually represent DNA by a series of base codes (e.g., 5' AATCGGATTGCA 3'). The base codes are usually arranged from the 5' end to the 3' end.

Because of specific base pairing in DNA (i.e., adenine (A) always bonds with (thymine (T) and cytosine (C) always bonds with guanine (G)) the complimentary stand to the sequence 5' AATCGGATTGCA 3' would be 3' TTAGCCTAACGT 5'.

With palindromes the sequences on the complimentary strands read the same in either direction. For example, a sequence of 5' GAATTC3' on one strand would be complimented by a 3' CTTAAG 5' strand. In either case, when either strand is read from the 5' prime end the sequence is GAATTC. Another example of a palindrome would be the sequence 5' CGAAGC 3' that, when reversed, still reads CGAAGC.

Palindromes are important sequences within nucleic acids. Often they are the site of binding for specific enzymes (e.g., restriction endobucleases) designed to cut the DNA strands at specific locations (i.e., at palindromes).

Palindromes may arise from brakeage and chromosomal inversions that form inverted repeats that compliment each other. When a palindrome results from an inversion, it is often referred to as an inverted repeat. For example, the sequence 5' CGAAGC 3', if inverted (reversed 180°), still reads CGAAGC.

See also Amino acid; Deoxyribonucleic acid (DNA); DNA replication; DNA synthesis; DNA technology; Gene mutation; Gene splicing; Mutagenesis.

palindrome

views updated Jun 11 2018

pal·in·drome / ˈpalinˌdrōm/ • n. a word, phrase, or sequence that reads the same backward as forward, e.g., madam or nurses run.DERIVATIVES: pal·in·drom·ic / ˌpalinˈdrämik/ adj.pa·lin·dro·mist / pəˈlindrəmist/ n.

PALINDROME

views updated May 14 2018

PALINDROME.
1. A WORD, PHRASE, or longer expression that reads the same backwards as it does forwards: for example, the words level and noon, and the phrases Madam, I'm Adam and Able was I ere I saw Elba.

2. Also REVERSAL, semordnilap (a backward palindrome). A word that spells another word when reversed: for example, doom, evil, warts, and the trade names Serutan, Trebor.

palindrome

views updated May 29 2018

palindrome a word, phrase, or sequence that reads the same backwards as forwards, e.g. madam, nurses run, or (in relation to Napoleon) able was I ere I saw Elba.

palindrome

views updated May 14 2018

palindrome XVII. — Gr. palíndromos running back again, f. pálin again + drom-, drameîn run.