Table 1:

Relative Expression of ERV genes in trophoblast over the course of human pregnancy

Gene Symbol	Chromosomal Location	d6–71	d8–122	1st Trimester3	Term4	TB from ESC4
ERVFRD-1	chr6: 11102721–11112071	+	+	+++	++	++
ERVW-1	chr7: 92097694–92107300	NL	+++	NL	+++++	++++
ERVV-1	chr19: 53517343–53519833	+/−	+++	+	++	+++
ERVV-2	chr19: 53044740–53051680	+/−	++	+	+++	++
ERVH48–1	chr21: 44336913–44345756	NL	+++	NL	+++	+
ERVMER 34–1	chr4: 53609603–53617807	+	+	++	+	+
ERV3–1	chr7: 64450732–64467124	+/−	+	NL	+	++
ERVK13–1	chr16: 2708389–2723440	NL	−	+/−	++	+

The asterisks are intended to show only relative expressions of the genes at a particular stage of pregnancy; they do not indicate relative expression between stages, since the data were acquired on different platforms and processed differently. NL means that the gene was not present among the listed genes, either because it was not expressed (unlikely for ERVW-1) or simply missing. Note that the data for days 6–7 and 8–12 are from in vitro cultured embryos developing in absence of a surrounding maternal environment and therefore lacking the physiological cues that might help guide normal development and gene expression. This caveat also applies to Term trophoblast where term cytotrophoblasts were cultured in vitro to promote syncytiotrophoblast formation.

¹Petropoulos et al. [4]

²West et al. [7]

³Okae et al. [52]

⁴Yabe et al. [9].