The Y-chromosome is one of the smallest chromosomes in the human genome and contains genes involved in male development and production of sperm. Previous research has shown that just two genes on the Y chromosome are necessary to make male mice who can sort of produce sperm. By “sort of” I mean that the mice … Continue reading No Y genes? No problem.
We have all heard that the sequence of human DNA differs from chimpanzee DNA by only about 1%. Yet humans are capable of building complex civilizations while the chimps are still eating bugs in the forest. If you compare the human brain to the brain of any other primate, it’s easy to see where our … Continue reading Bigger brains with Frizzled HARE
Eggs get ready for fertilization by producing and storing all the proteins necessary for early embryo development. After fertilization, there are a series of rapid cell divisions without growth, producing a lot of small cells (here's a video). At some point during this process, the embryo switches over from using the proteins from mom, to … Continue reading What big nuclei you have!
Remember when Dolly the sheep was cloned in 1996? That was the first cloned mammal and everyone freaked out thinking we would be cloning all our pets and even humans within a few years. Well, nearly 20 years have passed since then and reproductive cloning is still a very difficult and inefficient procedure. Most cloning … Continue reading Improving reproductive cloning
Female mammals have two copies of the X chromosome while males have only one copy (because they have a Y chromosome instead). Chromosomes contain genes and genes are the instructions for making proteins, so if females have twice as many copies of each gene on the X chromosome, will they make twice as much protein? … Continue reading The mosaic female brain
While preparing a class about synthetic biology, I came across this older paper that actually shows a practical application for synthetic biology. Kemmer et al. describe a new technique for artificial insemination of cows in the Journal of Controlled Release (in 2011). I’m not condoning these practices in cows; that is a debate for another … Continue reading Release the sperm!
Ever seen a pair of pigeons going at it? And did you notice a penis on the male pigeon? The answer is no, because most birds do not have external genitalia large enough for penetration. And yet birds reproduce via internal fertilization. Why would evolution favor male genitalia too small to actually enter into the … Continue reading (Insert mildly provocative title here)
There are two types of neurons in the brain: excitatory and inhibitory neurons. They do exactly what you think they would. Excitatory neurons release chemical messengers, which activate other neurons, which may eventually lead to some sort of perception or action. Inhibitory neurons release chemicals that silence other neurons. Why would you want inhibitory neurons … Continue reading Stop seizures with a brain graft
I’m back from an intense semester of learning and teaching Developmental Biology. One theme that emerged from my studies was that the development of organisms is centered around gene expression and cell to cell signaling. Often times, one cell will differentiate into its mature form, and then release a signaling protein that tells neighboring cells … Continue reading Go go gadget extendo filopodia
This week’s paper describes a new technique that could be used to manipulate human oocytes (i.e. eggs) to prevent a group of diseases called mitochondrial diseases. The paper was presented by Tachibana et al. in Nature along with a similar paper by Paull et al. For the sake of brevity, I will only discuss the … Continue reading Swapping eggs