Opinion: Is there an upper limit to genome size? ($)

There are only ten organisms known  to have genomes larger than 100 Gb in size and six of those are plants. Both Numbers 1 and 2 on the list are plants with genomes that are nearly 50x the size of the human genome (which is 3 Gb), and over 1000x that of Arabidopsis: the 148.8 Gb-genome Paris japonica (Japanese canopy plant), and the 147.3 Gb-genome wisk fern Tmesipteris obliqua. After surveying the size of all known genomes, Hidalgo and Pellicer et al. speculate that 150 Gb could be an upper biological genome limit. Why this would be the limit is less clear, but leading possibilities would seem to be high energy costs involved in DNA replication and repair, and basic cell-size packing constraints. (Summary by Aaron Rochette). Trends Plant Sci. 10.1016/j.tplants.2017.04.005