This paper by a team of researchers from several different universities has found a way to break the species barrier for making hybrid crosses. They somehow inhibited the expression of a pair of dna repair proteins during mieosis “whilst maintaining their mitotic expression”.
The ‘somehow’ is not stated in the abstract so I would be grateful for anyone who has access to this journal to pass that bit of knowledge along…
Current Biology, Volume 31, ISSUE 4, PR180-R181, February 22, 2021
Don, send me your email address.
Thanks very much Dr. Kuska.
So the answer is that they swapped out the promotor genes that control the genes for a pair of dna repair proteins. The native promotor acted during both mieosis and mitosis whilst the replacement promotor acts only during mitosis.
Such molecular manipulations are becoming standard fare with CRISPR technology. I would expect to see very rapid adoption of this technique for the creation of wide hybrids.
This raises an interesting question. Organisms modified using CRISPR mediated genetic transformation are not being governmentally regulated because the genes involved are intrinsic to the organism whereas organisms with genes that are inserted from other species are heavily regulated.
In this case, even though the replacement promotor gene may be intrinsic to the organism, the purpose of the transformation was to enable cross-species hybridization which, in fact, was carried out.
Should the resultant hybrid organism, created from two different species, be treated as a GMO for regulatory purposes?
I like your last paragraph!
To the last paragraph: I wouldn’t think so, unless somatic hybrids are also considered to be GMOs. Both processes merely involve lowering or bypassing the usual natural barriers to interspecific (or intergeneric!) hybridization in some way, but somatic hybrids are not regarded as GMOs. If the process does not itself contribute anything to result in the product being considered a GMO, and the parents weren’t already GMOs, then the hybrid produced with the aid of that process wouldn’t rightfully be regarded as a GMO, either. Of course, “GMO” is about as shaky of a concept as anything that humans have concocted in their short time on this planet.
Stefan
No opinion but risk averse so naturally an interview article with Doudna about CRISPR got my attention (CBS web news site).
Quote …
“ “The Code Breaker”: Jennifer Doudna and how CRISPR may revolutionize mankind”
… Cutting DNA like this usually disables a gene. We can disable a gene that gives us a disease, or shut off the gene that limits how much fur cashmere goats grow, or how much muscle a beagle grows.
The next step is much harder: Swapping in a different DNA sequence, replacing it with something we’ve created ourselves. We’ll be able to rewrite the genes of any plant, animal or person.“
This is not a magic elixir, but it is a point worth mentioning: crossability is often more about specimens than species.
Journal of Heredity 51: 13-14 (1960)
Male sterility in interspecific hybrids of Solanum
Raymond W. Buck, Jr.
“During hybridization and cytological investigation of tuber-bearing Solanum species and hybrids, the author observed a type of male sterility, as expressed by pollen abortion, in F1 hybrids involving certain clones of S. verrucosum Schlecht.”
“Crosses between S. verrucosum and diploid species from South America produce seed when S. verrucosum is the female parent. Most reciprocal crosses fail. However, the author suceeded in obtaining reciprocal hybrids with one clone of S. phureja Juz. & Buk. and with one clone of S. chacoense Bitt.”
Furthermore, two strains of S. verrucosum used as seed-parents gave only male-sterile hybrid progeny, while one other produced fully fertile offspring.
And another example:
Journal of Genetics 7: 91-94 (1916)
Note on the inheritance of “crossability”
W. O. Backhouse, B. A.
Wheat-Expert to the Argentine Government
Backhouse tried crossing various strains of wheat with rye, but had little success “— with one astonishing exception; a wheat of Chinese origin, for which I am indebted to Professor R. H. Biffen — a beardless vulgare — set 32 seeds out of 40 flowers fertilised with rye — or 80%. The seeds varied considerably in size and were all shrivelled.”
Three plants resulted, all sterile, though Backhouse noted that they flowered very early when there was little pollen about.
“It is interesting to note that this same Chinese variety crosses much less readily with durum wheat than with rye, and gives hybrids only about 1% fertile.”
Solanum phureja is also used to produce haploids of the common potato, S. tuberosum. Pollen of some S. phureja clones give clean haploids. Other clones also induce haploids, but with a small “genetic footprint” of Phureja DNA.