Alternative explanation SSRs
Throughout the genome, sequences exist that are repeated many times. Simple sequence repeats (SSRs) consist of related elements that each are less than 6 base pairs long. The number of times that they are repeated can differ between alleles on homologous chromosomes. Different alleles can be formed as a result of errors in pairing of the DNA strands, due to the repeated sequences.
Examples of different alleles:
CGGCTTTCGTATATATATATATATATATATTCGGCTCAGT
GCCGAAAGCATATATATATATATATATATAAGCCGAGTCA
CGGCTTTCGTATATATATATATATATATATATTCGGCTCAGT
GCCGAAAGCATATATATATATATATATATATAAGCCGAGTCA
CGGCTTTCGTATATATATATATATATATATATATTCGGCTCAGT
GCCGAAAGCATATATATATATATATATATATATAAGCCGAGTCA
CGGCTTTCGTATATATATATATATATATATATATATTCGGCTCAGT
GCCGAAAGCATATATATATATATATATATATATATAAGCCGAGTCA
CGGCTTTCGTATATATATATATATATATATATATATATTCGGCTCAGT
GCCGAAAGCATATATATATATATATATATATATATATAAGCCGAGTCA
CGGCTTTCGTATATATATATATATATATATATATATATATTCGGCTCAGT
GCCGAAAGCATATATATATATATATATATATATATATATAAGCCGAGTCA