Final answer:
Recent studies suggest that all humans can trace their ancestry back to a common female ancestor in Africa about 200,000 years ago, based on mitochondrial DNA and Y chromosome analysis.
Step-by-step explanation:
The recent studies of mitochondrial DNA (mtDNA) and variation in the Y chromosome strongly suggest that all humans can trace their ancestry back to a common female ancestor who lived in Africa about 200,000 years ago. Mitochondrial DNA is passed down from mother to offspring, allowing scientists to analyze the mutational relationships and estimate the timeline of genetic divergence. The Y chromosome, passed from father to son, provides additional evidence that all men today inherited a Y chromosome from a male ancestor who lived in Africa about 140,000 years ago.