TABLE 2.

Sex-specific groups of piRNAs

		Testis		Ovary		Testis and ovary
Group	Total no.	No.	%	No.	%	No.	%
1	92	0	0.00	92	100.0	0	0.00
2	59	2	3.39	54	91.53	3	5.08
3	35	3	8.57	30	85.71	2	5.71
4	34	0	0.00	34	100.0	0	0.00
5	34	4	11.76	30	88.24	0	0.00
6	33	0	0.00	33	100.0	0	0.00
7	27	0	0.00	25	92.59	2	7.41
8	27	10	37.04	5	18.52	12	44.44
9	26	2	7.69	21	80.77	3	11.54
10	25	19	76.00	1	4.00	5	20.00
11	24	1	4.17	21	87.50	2	8.33
12	24	2	8.33	22	91.67	0	0.00
13	23	1	4.35	20	86.96	2	8.70
14	22	2	9.09	16	72.73	4	18.18
15	21	1	4.76	20	95.24	0	0.00
16	20	0	0.00	20	100.0	0	0.00
17	20	1	5.00	18	90.00	1	5.00
18	19	4	21.05	13	68.42	2	10.53
19	19	0	0.00	19	100.0	0	0.00
20	18	3	16.67	12	66.67	3	16.67

The piRNAs are divided into groups, the first 20 of which are shown here. piRNAs in groups 1–7, 9, 11–13, 15–17, and 19 were exclusively or dominantly expressed in ovary, while only group 10 piRNAs were dominantly expressed in testis. Ovary-specific groups (1, 4, 6, 16, and 19) are in boldface type. The piRNA data are from both this study and Houwing et al. (2007).