Long interspersed repeated sequences of the mouse genome

Area of Science:

• Genomics
• Molecular Biology
• Bioinformatics

Background:

• Long interspersed repeated sequences (LIRSs) are abundant in mammalian genomes.
• Understanding the structure and variation within LIRSs is crucial for genome evolution studies.

Purpose of the Study:

• To characterize the sequence heterogeneity of a specific 6 kilobase (kbp) long interspersed repeat group in the mouse genome.
• To map the sites of sequence variation within this repeat family.

Main Methods:

• Reassociation of mouse DNA followed by single-strand nuclease digestion.
• Length resolution of DNA fragments using gel electrophoresis.
• Mapping of restriction endonuclease sites within cloned DNA fragments.

Main Results:

• Identification of discrete 15 kbp and 6 kbp DNA fragment groups from digested reassociated mouse DNA.
• The 6 kbp group, identified as the MIF-1 family, exhibits significant sequence heterogeneity.
• Heterogeneity sites were mapped using single-strand nuclease digestion of heteroduplexes and additional restriction endonuclease cuts.
• Specific restriction sites were mapped within a cloned 400 bp HindIII fragment of the MIF-1 family.

Conclusions:

• The MIF-1 family of long interspersed repeats in the mouse genome possesses notable sequence heterogeneity.
• The identified heterogeneity sites are localized and can be precisely mapped, providing insights into repeat evolution.
• One end of this relatively homogeneous LIRS has been clearly mapped.