Mark Megahan
A team of researchers at Colossal Biosciences crossed a woolly mammoth with a mouse. What they got wasn’t any larger than normal but has “curly whiskers” and “wavy, light hair that grows three times longer” than normal. Bringing the mammoth back from total extinction is a lot harder than anyone imagined. This is a huge step in the right direction.
Colossal woolly mouse
Dallas, Texas, based Colossal Biosciences genetically modified an ordinary lab mouse to splice in “several woolly mammoth-like traits.” It’s all part of an effort “to resurrect the mammoth and other extinct animals.”
Their modified mice let the team “test hypotheses about the link between specific DNA sequences and physical traits.”
Colossal is trying to figure out how the mammoth was able to “adapt to life in cold climates.” They were all over the place until they suddenly died out all at once around 4,000 years ago.
They can’t just clone one from the existing DNA samples like they do with sheep and other mammals. That’s where the mouse comes in.
According to chief science officer Dr. Beth Shapiro, “It is an important step toward validating our approach to resurrecting traits that have been lost to extinction and that our goal is to restore.”
They told the world about the designer genes in their mouse on Tuesday, March 4. Dr. Shapiro “is currently on a leave of absence from her role as professor of ecology and evolutionary biology at the University of California, Santa Cruz.”
Genetic variants
The researchers took sample DNA sequences and spliced them in to create the woolly mouse. First, they “identified genetic variants in which mammoths differed from their closest living relative.”
That would be the Asian elephant. Mice are much easier to work with in the lab.
“The company’s scientists then pinpointed 10 variants related to hair length, thickness, texture, color and body fat.” These variants all had one thing in common. They also “corresponded to similar, known DNA variants in a lab mouse.”
For instance, they were able to figure out that “fibroblast growth factor 5” happens to target “the cycle of hair growth, creating longer, shaggy hair.” That’s only the beginning of the fashionable hairstyle.
“They also altered the function of three genes related to hair follicle development and structure to create woolly hair texture, wavy coats and curled whiskers.” They adjusted the melanocortin 1 receptor to “produce mice with golden hair rather than the usual dark fur.” They also included “a variant associated with changes in body weight.”
In the peer review of their report, one picky colleague notes there’s no proof the mammoth mouse can tolerate cold. “As it is, we have some cute looking hairy mice, with no understanding of their physiology, behavior, etc.“
