Comparative genomic analysis reveals occurrence of genetic recombination in virulent Cryptosporidium hominis subtypes and telomeric gene duplications in Cryptosporidium parvum

Table 4 Species-specific genes in genomes of Cryptosporidium parvum and C. hominis

Chromosome	Length (bp)	Genes	Specificity
8	19,048	cgd8_680, cgd8_690 and other potential genes in 10,000 bp sequence gap	C. parvum
6	15,314	cgd6_5480, cgd6_5490, cgd6_5510, cgd6_5520	C. parvum
5	5,620	cgd5_4580, cgd5_4590, cgd5_4610	C. parvum
3	~4800	Chro.50011	C. hominis

Notes:
1. cgd5_4580, cgd5_4590, cgd5_4600, and cgd5_4610: four genes with similar sequences at the 3′ end of chromosome 5 in C. parvum, all called telomeric MEDLE family of secreted proteins. C. hominis has only one such gene here (Chro.50507, the ortholog of cgd5_4600).
2. cgd6_5480 and cgd6_ 5490: two genes of the telomeric MEDLE family of secreted proteins with similar sequences at 3′ end of chromosome 6 in C. parvum. C. hominis has no such gene here. The two genes have sequences similar to the four genes above. This fragment and cgd6_5510 (ZPT) and cgd6_5520 below are located at the 5′ end of chromosome 5 in the C. hominis genomes sequenced. C. hominis specimen 37999 does not appear to have the ortholog for cgd6_5470, although 30976 clearly has it. Ortholog of cgd6_5500 is apparently translocated to an unknown chromosome in C. hominis, downstream of the ortholog of cgd5_4580.
3. cgd6_5510 (ZPT) and cgd6_5520: telomeric insulinase-like protease with a signal peptide (the two genes have very different sequences). C. parvum has 11 such genes near 3′end of chromosome 3.
4. cgd8_680: a large low complexity protein with repeats. cgd8_690: a signal peptide containing protein with 2 Cryptosporidium-specific paralogs (cgd8_660 and its ortholog chro.80081).

ISSN: 1471-2164