Earth before life

Caren Marzban,Ulvi Yurtsever,Raju Viswanathan

doi:10.1186/1745-6150-9-1

Abstract

BackgroundA recent study argued, based on data on functional genome size of major phyla, that there is evidence life may have originated significantly prior to the formation of the Earth.ResultsHere a more refined regression analysis is performed in which 1) measurement error is systematically taken into account, and 2) interval estimates (e.g., confidence or prediction intervals) are produced. It is shown that such models for which the interval estimate for the time origin of the genome includes the age of the Earth are consistent with observed data.ConclusionsThe appearance of life after the formation of the Earth is consistent with the data set under examination.ReviewersThis article was reviewed by Yuri Wolf, Peter Gogarten, and Christoph Adami.

Highlights

A recent study argued, based on data on functional genome size of major phyla, that there is evidence life may have originated significantly prior to the formation of the Earth
The region between the black, dashed curves is the 95% prediction interval for the ordinary least-squares fit. According to this prediction interval life may have originated as early as 7 billion years ago
A naïve regression model relating genome size to the age of life suggests that life may have formed prior to the Earth’s formation

Summary

Introduction

A recent study argued, based on data on functional genome size of major phyla, that there is evidence life may have originated significantly prior to the formation of the Earth. Sharov [1], and more recently, Sharov and Gordon [2] reported an analysis of data on the evolution of genetic complexity during the history of life on Earth These two works - hereafter denoted SG - use the functional genome size of major phylogenetic lineages, as a measure of genetic complexity, and show that it has an exponential relationship with the estimated dates of the transitions where these lineages first originated. A second aspect of the SG regression fit is that it does not incorporate statistical uncertainty due to sampling variability, e.g., through confidence or prediction intervals The inclusion of such intervals can lessen the misleading impacts of extrapolation, because they generally widen as one moves away from the mean of the data [4]. Values outside of the interval may be rejected (with some confidence), but all of the values within the interval are possible, and “likely.” As such, consideration of interval estimates is important because it can mitigate misleading conclusions

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Conclusion