“…Many of these are processed, intron-less pseuodogenes, notably those related to the simple epithelial keratin genes K8 and K18, for which there are nearly 150 pseudogenes in the human genome (Hesse et al, 2001). Other keratins have conventional intron-containing pseudogenes, in particular the keratins involved in PC, namely K6, K16, and K17 (Troyanovsky et al, 1992;Takahashi et al, 1995;Smith et al, 1999b). The presence of pseudogenes whose sequences are highly homologous to the functional gene, makes genetic analysis difficult using genomic DNA, as discussed below.…”