Table 1.
Section | Observation | Interpretation by proponents of neo-oogenesis | Alternative explanation consistent with a fixed oocyte reserve. |
---|---|---|---|
2.(i) | BrdU-incorporation in Mvh+ germ cells located in the OSE [7,10]. |
Mitosis in germline stem cells. |
MtDNA synthesis, and DNA recombination and repair in tardy oocytes, in the neonatal ovary. |
Mvh+ germ cells located in the OSE [7-9]. | Existence of a germinal epithelium. | Oocytes in transit across the OSE during exfoliation [54]. | |
2.(ii) | "Oocyte-like" phenotype of cells in OSE-derived cultures [8,9]. | De novo formation of immature and secondary ocytes from stem cells. | Nondescript cells undergoing oncosis. |
Small, round cells, above and below the OSE [9]. | Putative female germline stem cells. | Small immune cells in the OSE [54]. | |
"Embryoid body-like" and "blastocyst-like" structures [9] in OSE-derived cultures. | Pathenogenetic activation of de novo oocytes. | Nondescript cellular aggregates, and vesicles of OSE. | |
Expression of Oct4, Sox2, Nanog and c-kit by OSE derivatives [9]. | Embryonic-like, germline stem cells. | Cultures containing regenerative epithelium [58]. | |
Cell lines producing early oocytes [11]. | Female germline stem cell lines. | Mixed cultures of OSE, early oocytes and/or oogonia. | |
2.(iii) | BU-induced depletion of the follicle pool [7,15] and extinction of fertility. | Destruction of replicative, female germline stem cells by BU treatment, without atresia. | Induction of oocyte atresia by BU treatment; and proof of absence of female germline stem cells. |
2.(iv) | EGFP+ cells with germ-cell markers in ovaries of CT-treated mice following BMT or PBCT [12,13]. | De novo oocytes from bone marrow-derived precursors. | Oct4-expressing macrophages; and autofluorescent, somatic cells of the ovary. |
Presence of PGC and HSC in extraembryonic regions during early post-implantation development [12]. | Incorporation of oocyte precursors within the haematopoietic system. | Distinct temporal and spatial niches for the origins and migration of germinal and haematopoietic lineages. | |
2.(v) | Replicative, unipotent oocyte-like cells [10]. | Existence of female germline stem cells. | Residual oogonia induced to proliferate by specified culture conditions, and expansion of populations of functional oogonia. |
Immuno-magnetic isolation of Mvh+ proliferating cells from disaggregated ovaries [10]. | Selective purification of stem cells via Mvh binding to anti-Mvh antibody. | Harvesting of oogonia and primary oocytes due to Mvh binding to anti-Mvh antibody, or to Fc receptors on the plasma membrane of oogonia and oocytes binding to Fc moiety of antibody. | |
3. | Restoration of the host follicle pool in CT-treated mice following BMT [12,13]. | Stimulation of endogeneous, de novo oogenesis. | Induction of autoimmunity to ovarian antigens by CT; and rescue of fertility via tolerance restored by haematopoietic chimaerism. |