Final answer:
The estimated split between chimpanzee and hominin line from a common ancestor happened about six million years ago based on genetic studies and fossil records.
Step-by-step explanation:
The current estimate based on comparative genomics for a split of the chimpanzee and hominin line from a common ancestor is about six million years ago.
According to genetic studies, humans and chimpanzees diverged from each other between 5 - 7 million years ago. Fossil records also support this timeline, with species like Sahelanthropus tchadensis living right at the time of the divergence. Comparing the genes of living species is one way scientists determine their relationship, and humans and chimpanzees share about 98% of their genes, showing our close evolutionary connection.