Single copy DNA has a unique sequence of DNA and codes for protein and are sites of transcription. The repetitive sequence of DNA has repeated sequences of nucleotides, and these do not code for proteins.

The single-copy DNA is a long unique sequence of nucleotides in the DNA. These are mainly found in the exons as they are coding regions and are the sites for transcription to make mRNA. These are present in the euchromatin part as they are coding regions. These are similar in many individuals.

The repetitive sequence of DNA is a short sequence of repeated nucleotides in the DNA. These are mainly found in the introns and other noncoding parts of the DNA.  They do not code for protein synthesis. These are present in the heterochromatin part as they are noncoding regions. They are unique in different individuals.

Key Points

• Single-copy DNA is a unique sequence that code for proteins and undergoes transcription. These are found in exons or the euchromatin.

• Repetitive DNA is the sequence that has repeated sequences of nucleotides in the DNA and that don’t code for proteins. These are found in introns or the heterochromatin.

Key Terms

euchromatin: part of a chromosome that is involved in transcription

heterochromatin: part of a chromosome that is not included in transcription and has suppressed genes

introns: noncoding sections of an RNA transcript that are spliced out before the RNA molecule is translated into a protein.

exons: the sections of DNA (or RNA) that code for proteins

transcription: the copying of a gene’s DNA sequence to make an RNA molecule

nucleotide: a compound consisting of a nucleoside linked to a phosphate group, the basic structural unit of nucleic acids such as DNA