A palindromic nucleotide sequence is capable of forming a hairpin. The stem portion of the hairpin is a "pseudo-double stranded" portion since the entire hairpin is a part of same (single) strand of nucleic acid. Palindromic motifs are found in most genomes or sets of genetic instructions. They have been specially researched in bacterial chromosomes and in the so-called Bacterial Interspersed Mosaic Elements (BIMEs) scattered over them. In 2008, a genome sequencing project discovered that large portions of the human X and Y chromosomes are arranged as palindromes. A palindromic structure allows the Y chromosome to repair itself by bending over at the middle if one side is damaged.