An investigative panel probing the validity of Hwang Woo-suk's stem cell research says it will announce this weekend the results of a DNA analysis on his stem cells and teratoma.

An inside source said Thursday that the panel has collected many samples in its investigation and that the analysis by three independent organizations will take time.

Accordingly, an announcement Friday on the DNA analysis is unlikely in the probe's news briefing on the interim results of its probe on Hwang.

Meanwhile, the panel said that it grilled Wednesday two co-authors of Hwang's thesis, Roh Sung-il and Moon Shin-yong, Hwang's top assistant Ahn Cu-rie and a producer of the MBC TV news magazine "Producer Notebook," Han Hak-soo.