Russia has reportedly been taking saliva samples from religiously conservative Muslim women.
The DNA would be used to identify body parts should any of the women carry out suicide bomb attacks on Olympic targets at the Sochi Winter Olympics, Reuters said.
Eight Dagestani women contacted by the news agency had been asked to provide swabs of saliva.
Locals said the DNA tests were part of a sweep after a suicide bombing in the capital Makhachkala in May.
The move coincides with a crackdown by President Vladimir Putin on an Islamist insurgency in Dagestan, which lies east of the Sochi Games sites.
Dubbed "black widows", about 49 female suicide bombers have carried out attacks in Russia in the past 13 years, Aljazeera reported.
In response, security forces have blown up the homes of militants' relatives, sealed off mountain villages, closed schools and rounded up young men suspected of having ties to militants.
Critics say the new hard line being taken by Mr Putin is feeding the resentment that lies behind insurgent attacks in the region.
TOP STORIES OF THE DAY
In July, Doku Umarov, the leader of the Islamist insurgency, urged his fighters to use "maximum force" to sabotage the Sochi Olympics.
Although the security crackdown has resulted in many Salafis fleeing abroad, others have stayed and taken up arms, their leaders say.
Mr Putin, who is spending $50bn (£31bn) on the Games, has tightened security around Sochi, where Cossack militia patrol the streets.
Interior Minister Vladimir Kolokoltsev told the Russian parliament the authorities were receiving "alarming information" and were working to eliminate leaders and members of armed groups, Sky News reported.
"There are simply no other ways to combat these inhuman monsters," he said.