Wastefulness doesn't stop civilizations from doing something. It could be the spaceship equivalent of a SUV.
In fact, it came from me looking at human and other vertebrate genomes, and then looking at some reference "crop" genomes and seeing multiples as many genes. I didn't know if they are polyploid copies as you say or not tho it could have been. I'll try to find the links where I saw these numbers (from a few years ago now) and update.
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Ok, for example:
chimpanzee genome, https://www.ncbi.nlm.nih.gov/genome/genomes/202? , size: ~3Gb, scaffolds: ~50k
bread wheat genome, https://www.ncbi.nlm.nih.gov/genome/genomes/11?, size: ~13Gb, scaffolds: ~750k
And more summaries are at the Wikipedia page of sequenced plant genomes:
https://en.wikipedia.org/wiki/List_of_sequenced_plant_genome...
( there are many with over 30,000 genes ( cf humans < 20,000 ) and there are a few big ones ( Aegilops tauschii (Tausch's goatgrass) has 4.3Gb ), and most are more than 200 Mb ( cf fruit fly is around 180Mbp )
When compared with small insects and animals ( https://en.wikipedia.org/wiki/List_of_sequenced_eukaryotic_g... ) plants often have larger genomes. And in some cases larger genomes than humans.
The weird thing is that genome size is correlated with "complexity" in non-animal world too. With fungi and so on having smaller genomes generally than large plants. All this seems weird because my assumption is that animals are more "complex" than plants. So either there is a lot of redundancy there or plants have some kind of unseen complexity. It would be cool to see models that try to quantify the explanations of large genomes given here by others ( error and viral resistance and freer nuclear sizing ) and see if those models can account for the sizes somehow, or if there might be more to the picture.
Another possibility is that genomes grow with genetic manipulation so cross-breeds have bigger genomes. But what does that say for humans? Are we the result of genetic breeding as well?
(This is also why plants tend to be full of weird organic molecules like terpenes, which are beneficial to nearly every animal alive today: those chemicals probably protected them from something at some point, and the genes responsible for making them have had no reason to be shut off since then.)
But animals, with a finite limit on gene-base size, must solve problems differently. Animals evolve along different lines—polyploid mutations usually result in non-viable offspring for animal species, because animals frequently have mutations that assume diploidy, with complex machinery to favor better vs. worse versions of each diploid gene using silencing or epigenetic methylation. And more generally, animals evolve solutions to whole classes of problems that have compact genetic representations. We don't have a million custom immune responses; instead, we have xenograft rejection genes, T-cells, livers and kidneys, saliva and stomach acid, the sensation of itching, skin that sheds and skin oil that clears pores, and put together, those mechanisms handle 99% of cases just fine.
And often we don't need any of those; the primary "solution" that animals have to almost every problem, is just the ability to move away from the source of the problem. If there's a predator, you can just run away. You don't need to know what the thing is, to run away from it; you just run away! Universal solution! To do that, we need a lot of things: not just limbs, but sensory organs, to know where we are and where the predator is; and nerves, to link the two; and even some sort of instinct for what predators exist, or memory to record sense-fear associations. But all those genes still take up far less space than immune proteases individualized for every bacterium and fungus on earth.
1 http://onlinelibrary.wiley.com/doi/10.1111/j.1095-8339.2010....
I bought my first SUV a few weeks ago. It's a Jeep renegade, thus not very big, still the comfort from big space inside (without a huge 2-D surface) is priceless.
But that mention of the Defender sent me looking, and I really like how it looks. But unless I get a much better (much, much better!) job somewhere, I can't even afford a used one. There are ones on CL right now in my area, dating from the 80s (but with low, low miles for some reason) selling for close to 90K - and if I'm going to spend that kind of money locally, I might as well get a Local Motors Rally Fighter!
Honestly, though, what I would love to own isn't for sale yet, and if they ever do finish them for sale, likely they won't sell them to anyone in the US:
...though they should be legal to drive, as a "kit car" (though probably deadly in a collision on our streets).
More importantly, the SUV will haul my (small) yacht but it's a strain on the mini-van.