The samples were taken Tuesday, a day after investigators said they would conduct DNA tests on blond hair attached to duct tape that was found along Aruba's northeastern coast, in a possible break to the six-week-old disappearance of Natalee Holloway.
Beth Holloway Twitty, Natalee Holloway's mother, told The Early Show she is hoping for the best.
"I'm so grateful to the individual, the park ranger that made that discovery," she said, "How observant of him, because, you know, I think it could be a critical piece of evidence."
Dutch youth, Joran van der Sloot, 17, was taken to a hospital and submitted a saliva sample for the genetic testing sought by prosecutors, his attorney Richie Kock said.
Two Surinamese brothers, Satish Kalpoe, 18, and Deepak Kalpoe, 21, who were detained earlier in the case but released, also submitted saliva samples the same day, said Ruud Offringa, an attorney for the older brother.
Authorities told defense attorneys the DNA would be compared to material found by investigators, but did not disclose what would be used in the comparison, Offringa and Kock said.
Van der Sloot and the brothers were the last people known to have seen Holloway before she vanished May 30. They have not been charged and all three maintain their innocence.
They were arrested June 9, but a judge ordered the Kalpoe brothers released July 4 for lack of evidence. The judge ordered van der Sloot to remain in custody until Sept. 4, when prosecutors must present arguments again if they want to prolong the detention.
The saliva specimens will be sent to the Netherlands, and it could take a week or two for the findings to be disclosed, Offringa said. The test to determine if the hair came from Holloway also will take place in the Netherlands.
Aruba, a Dutch protectorate, doesn't have a lab to conduct the genetic testing.
A spokesman for the Aruban government, Ruben Trapenberg, declined to comment Wednesday on the investigation, and the prosecutor could not be reached.
The FBI, which has been advising in the investigation, has said it would conduct separate genetic testing on the hair.
A park ranger found the duct tape while collecting trash Sunday on the opposite side of the island from where the 18-year-old honors student was last seen in public.
Holloway disappeared on the last day of a vacation with 124 classmates to celebrate their high school graduation. Extensive searches by Dutch marines, Aruban police, and some 2,000 volunteers have found no trace of her.
A volunteer search organization from Dickinson, Texas, that pulled its team from the island on Sunday said it planned to dispatch three people to the Caribbean island on July 28 with ground-penetrating radar.