Question

You have begun to characterize a sample obtained from the depths of the oceans on Europa, one of Jupiter's moons. Much to your surprise, the sample contains a life-form that grows well in a rich broth. Your preliminary analysis shows that it is cellular and contains DNA, RNA, and protein. When you show your results to a colleague, she suggests that your sample was contaminated with an organism from Earth. What approaches might you try to distinguish between contamination and a novel cellular life-form based on DNA, RNA, and protein?

Answer 1

To distinguish between contamination and a potential Europan life-form, scientists could perform genetic sequencing, isotopic analysis, study biochemical pathways, and use morphological comparison. These analyses could reveal unique characteristics that suggest a non-terrestrial origin if they do not match any known earthly organisms.

Step-by-step explanation:

To differentiate between contamination from Earth and a novel life-form in a sample from Europa, the following approaches could be considered:

• Genetic Sequencing: Perform detailed DNA and RNA sequencing. Compare the sequences obtained to existing databases of Earth organisms. If the genetic material does not match any known earthly organisms, it may suggest a non-terrestrial origin.
• Isotopic Analysis: Look at the ratios of certain isotopes within the organic material. These isotopic ratios can be distinct between different planetary bodies, depending on their formation and evolutionary history.
• Study of Biochemical Pathways: Examine the metabolic enzymes and pathways present in the sample. Unique biochemistry not found in Earth organisms could indicate an extraterrestrial life-form.
• Morphological Comparison: Use electron microscopy to study the morphology of the cells. Any structures that are not consistent with Earth-based life could suggest an alien origin.

Additionally, ensuring rigorous sterile techniques during the collection and analysis of samples is crucial to prevent contamination and strengthen the case for a non-Earthly life-form.