Palindromic SNP is also known as ambiguous SNP, in which SNPs whose alleles correspond to nucleotides that pair with each other in a double-stranded DNA molecule. A DNA sequence is a palindrome if the 5’ to 3’ (positive or forward) sequence is the same as the 3’ to 5’ (negative or reverse). For instance, the sequence ACTAGT (5’ to 3’) is a palindrome because its complementary sequence is TGATCA.
References:
Hartwig, Fernando Pires et al. International journal of epidemiology vol. 45,6 (2016)