DNA does not last indefinitely
DNA molecules fragment and chemically degrade after death. A study of dated bones estimated a DNA half-life of about 521 years under its measured conditions, with preservation strongly dependent on temperature and burial environment.
The record is millions, not tens of millions, of years
The oldest sequenced environmental DNA currently comes from Greenland sediments around two million years old. That is extraordinary, but still more than thirty times younger than the last non-avian dinosaurs.
Why amber does not rescue Jurassic Park
Early claims of dinosaur-age DNA from insects in amber did not survive modern contamination controls. Even if an insect had fed on a dinosaur, the genome would have to remain identifiable for roughly 66 million years.
Could we build something dinosaur-like instead?
Gene editing can alter living birds and developmental biology can reveal ancestral pathways, but an engineered bird with selected ancestral traits would not be a cloned Tyrannosaurus or Velociraptor.
Research record
Allentoft et al. (2012) — the half-life of DNA in bonePeer-reviewed · open sourceKjær et al. (2022) — two-million-year-old environmental DNAPeer-reviewed · open sourceCould We Ever Clone a Dinosaur?
Direct answer: With known biology and preservation chemistry, no. We do not have recoverable non-avian dinosaur genomes, and cloning cannot reconstruct a genome that has been chemically destroyed.
Jurassic Park-style cloning is not supported by ancient-DNA evidence. Future engineering may create organisms with selected dinosaur-like traits, but that is reconstruction, not resurrection.