Category: DNA

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Cattle domestication

I was going to write about some recent papers on the domestication of cattle myself, but things got a bit hectic and I didn’t find time. I did, however, find Razib’s post at Gene Expression, and I commend it to you. Of course there’s a lot in there about the genes for milk production, and some worrying nonsense about using genome information to breed better cattle or, to put it another way “accelerating livestock genetic improvement for milk and meat production”. Breeders making use of super-sires and super-ovulating cows have already done a pretty good job of reducing the diversity of extant cattle, and I for one am not convinced by the need for ever more efficient use-once-then-dispose-of milk machines. But I haven’t read the papers, so I can’t comment further. I am intrigued, however, by this statement, quoted by Razib:

Domestication and artificial selection appear to have left detectable signatures of selection within the cattle genome, yet the current levels of diversity within breeds are at least as great as exists within humans.

If we’re not suffering from having passed through genetic narrows, maybe cattle aren’t either. Maybe they’re just suffering.

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Nibbles: Japan, Bananas, GMO, Bees, Squirrels, Mangroves, Climate change and indigenous people, Goji, Svalbard, Heirloom rice, Dataporn

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How C4 came to be understood

Yesterday was Ada Lovelace day, when bloggers around the world celebrated women in technology. We weren’t aware of it, and frankly, I’m not sure who we might have chosen. Erna Bennett? Fortunately, though, we can direct you instead to Oliver Morton’s fine post on Constance Hartt. Who she?

Hartt was a laboratory researcher at the Hawaiian Sugar Planters Association Experiment Station, and her assiduous work on the biochemistry of sugar cane in the 1930s and 1940s convinced her that, for that plant at least, the primary product of photosynthesis is malate, a four carbon sugar. Later carbon-14 studies showed that she was right — and led to an interesting conundrum. Why did some plants — most plants, indeed, and almost all algae — make a three carbon sugar, phophoglycerate, while sugar cane and, it later became clear, various other grasses made a four-carbon sugar?

Some gene-jockeys seem to think that all that’s needed to double the yield of crop plants is “simply” to give them a C4 photosynthetic pathway. I’m not going to get into that one. But Morton gives a good account of how and why C4 differs from C3, and the part Hartt played in its elucidation.

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Nibbles: Book, Moral and physical revulsion, DNA bank, Cacao genome, Cassava, Agroforestry, Dung products, Pork brain

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Good news for wheat

Two studies out in the past week in Science are going to help wheat breeders fight diseases. One identified a DNA sequence — for a product known as the Lr34 transporter protein — which seems to confer protection against no fewer than three fungal diseases. And another study showed that a (different) DNA segment (called Yr36), which had previously been introgressed into durum wheat from wild emmer, also conferred rust resistance in the field (via). Gene discovery strikes again.