Nucleic Acid Terminology
Molecular Diagnostics
(MDx) Review 524
TERM EXPLANATION
Nucleic acid
Deoxyribonucleic acid (DNA)
dsDNA
ssDNA
Genomic DNA
Mitochondrial DNA
Chromosome
Gene
Exons
DNA & RNA
Nucleic acid that carries genetic information. In eukaryotes, located in chromosomes in nucleus & small
amount in mitochondria. Also present in bacteria & DNA viruses.
Double-stranded DNA.
Single-stranded DNA.
DNA in chromosomes.
Circular piece of DNA found in mitochondria of eukaryotes. Codes for polypeptides involved in oxidative
phosphorylation. Transmitted by maternal inheritance (mitochondria in ova, not sperm). Used in
forensics, lineage & population studies.
Piece of coiled DNA containing many genes. Humans have 23 pairs of chromosomes. 1 set from mother,
1 from father. 22 pairs of autosomes, 1 pair sex chromosomes (X,Y).
Specific sequence of nucleotides (1,000–4,000) at particular location on chromosome. Starts at 5’ end
with promoter region that initiates transcription & ends at 3’ end with terminator sequence that ends
transcription. Humans have about 30,000 genes. DNA sequence in genes is 99.9% the same in all people.
DNA sequences on chromosomes that code for amino acids/proteins.
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