Thanksgiving is full of tension. With Plant Humor’s help, you can casually redirect the conversation to what people really care about- that a multinational team of scientists just decoded pumpkins’ DNA! Here’s our play-by-play with helpful stock photos.
- Wow, that’s a big, juicy-looking bird! You know what else is big? The Cucurbita genome! Cucurbita species- pumpkins, gourds, and squash- have 40 chromosomes and around 32,000 protein-coding genes. Their close relatives, cucumbers, have just 14 chromosomes and around 26,000 protein-coding genes. For a non-plant comparison, humans have 46 chromosomes and around 19,000 protein-coding genes. That means that a pumpkin has 13,000 more genes than a human! (The human genome size including “junk” and noncoding DNA is larger than a pumpkin’s- but still!)
- I see a lot of sneezing children here tonight, but I’ve got an immune system of steel! You know what else is hardy and disease resistant? The “Shintosa” hybrid pumpkin variety, a cross between Cucurbita maxima (eg buttercup squash) and Cucurbita moschata (eg butternut squash). That’s why researchers decided to sequence the DNA of “Shintosa”, along with the two parental varieties, so that they could learn about its cool traits!
- Adding ramen to coleslaw, and marshmallows to everything else, mixes so many cuisines! You know what else is a mix? All pumpkins and squashes. They had two ancestors of different species. You can trace entire Cucurbita chromosomes back to one ancestor or the other because not much mixing has happened since. So “Shintosa” is a hybrid… of a hybrid!
- I can’t believe that Grandma lifted that twenty-pound tureen of gravy- she’s unstoppable! You know what else is surprisingly healthy? “Shintosa”, because it contains higher levels of beta-carotene and lycopene than either C. moschata or C. maxima. Because all pumpkins had two separate ancestors, they have two sets of an important gene that helps produce beta-carotene and lycopene. C. moschata only uses one of those two copies, and C. maxima only uses the other one. But “Shintosa” uses both ancestral copies, so it gives you more healthy goodness.
- Mmm, pumpkin pie! … (beat) … On a totally unrelated note, in no way pertaining to the pie, isn’t it cool that they sequenced the Cucurbita genome?
Sources & Further Reading:
Sun H., Wu S., Zhang G., Jiao C., Guo S., Ren Y., Zhang J., Zhang H., Gong G., Jia Z., Zhang F., Tian J., Lucas W.J., Doyle J.J., Li H., Fei Z., and Xu Y. (2017). Karyotype Stability and Unbiased Fractionation in the Paleo-Allotetraploid Cucurbita Genomes. Mol. Plant. 10: 1293-1306.
Chi, K.R. (2016). The dark side of the human genome. Nature 538: 275-277.