Now that summer’s here, have you noticed that the mosquitoes are out in full force? Did you know that mosquitoes cause more human suffering and disease than any other organism on the planet? Over 750,000 people a year die from mosquito-borne illnesses, and it’s not just humans that are affected! Mosquitoes spread dog heartworms, Eastern equine encephalitis, and many other diseases that affect our pets and local wildlife. But there might soon be a solution!
Researchers have figured out a way to genetically engineer mosquitoes that could dramatically reduce or eliminate some mosquito-borne illnesses. In these mosquitoes, when sperm is produced, the X chromosome that the male would normally pass on to its female young is destroyed, so 95% of the time they only have male offspring. Why does this matter? Well, male mosquitoes don’t bite- the females do. Females spread disease, and one female can lay up to 3,000 eggs over the course of her lifetime.
Hopefully, this type of pest control could eliminate many mosquito-borne illnesses. But could this type of gender control work in other species? Could this research have applications in the understanding and management of X-linked diseases? What do you think?
It’s been known for decades that the incidence of acute lymphoblastic leukemia (ALL) is 20 times higher in children with Down syndrome than in the general population. And now- thanks to mice- researchers know why!
People with Down syndrome have an extra copy of part or all of chromosome 21. And by working with mice that carry extra copies of genes that are found on chromosome 21, researchers have identified the link between Down syndrome and ALL. Long story short, this particular type of leukemia is caused by an excess of abnormal white blood cells that are supposed to fight infections but don’t work properly. These mice led researchers to the specific proteins involved in this process, and they found- and confirmed in human cell samples- that the gene responsible for spurring the creation of these abnormal cells was an extra gene on chromosome 21. Link: discovered.
While there currently aren’t any drugs that target this specific gene, researchers now know where to focus. Now that they know where the problem lies, they can work to develop drugs that could potentially reduce the chances of a child with Down syndrome developing leukemia! It’s also possible that ALL patients without Down syndrome could benefit from this research.
It’s not good news yet; there’s still work to be done. But I support the fight against pediatric cancer- and the mice do, too!
There are over 1,000 X-linked genes, including the genes for red-green color blindness, hemophilia, male pattern baldness, and body fat distribution. And if you remember your high school genetics, males have one “X” and one “Y” chromosome, and females have two “X” chromosomes.
Since females have two “X” chromosomes, only one of the X chromosomes will be expressed in any given cell. The determination of which one is expressed is random. Tortoiseshell and calico cats (all females) are the perfect example- they have a gene for orange fur on one of their X chromosomes, and a gene for black fur on the other. Their random coat patterns are due to the random expression of X-chromosomes; areas where the fur is black express the X-chromosome with the black fur gene, and areas where the fur is orange express the X-chromosome with the orange fur gene.
OK, so the cats look pretty awesome. But it doesn’t stop there. Researchers are working with calico cats to try to understand how X-chromosomes are inactivated, in an attempt to figure out a way to turn certain genes on or off in a way that isn’t random. How cool would it be if genes linked to obesity or other diseases could be selectively silenced without altering a person’s DNA? Or if X-chromosome linked disorders could be silenced in a way that they wouldn’t be passed down to our offspring?