chromosomes
edyong | March 17, 2010In Robert Louis Stevenson's classic story, Dr Henry Jekyll drinks a mysterious potion that transforms him from an upstanding citizen into the violent, murderous Edward Hyde. We might think that such an easy transformation would be confined to the pages of fiction, but a similar fate regularly befalls a common fungus called Fusarium oxysporum.
A team of scientists led by Li-Jun Ma and Charlotte van der Does have found that the fungus can swap four entire chromosomes form one individual to another. This package is the genetic equivalent of Stevenson's potion. It has everything a humble, Jekyll…
edyong | March 10, 2010The animal on the right is no ordinary chicken. Its right half looks like a hen but its left half (with a larger wattle, bigger breast, whiter colour and leg spur) is that of a cockerel. The bird is a 'gynandromorph', a rare sexual chimera. Thanks to three of these oddities, Debiao Zhao and Derek McBride from the University of Edinburgh have discovered a truly amazing secret about these most familiar of birds - every single cell in a chicken's body is either male or female. Each one has its own sexual identity. It seems that becoming male or female is a very different process for birds than…
edyong | February 21, 2010Whiptail lizards are a fairly ordinary-looking bunch, but some species are among the strangest animals around. You might not be able to work out why at first glance, but looking at their genes soon reveals their secret - they're all female, every single one. A third of whiptails have done away with males completely, a trick that only a small minority of animals have accomplished without going extinct.
Some readers might rejoice at the prospect of a world without males but in general, this isn't good news for a species. Sex has tremendous benefits. Every fling shuffles the genes of the two…
edyong | June 5, 2009For humans, sex is a simple matter of chromosomes: two Xs and we become female; one X and a Y and we develop into males. But things aren't so straightforward for many lizards - many studies have found that the temperature of the nest also has a say, even overriding the influence of the chromosomes. But the full story of how the lizard got its sex is even more complicated. For at least one species, the size of its egg also plays a role, with larger eggs producing females, and smaller ones yielding males.
The discovery comes from Richard Shine's group at the University of Sydney. In earlier…
grrlscientist | March 15, 2008tags: genetics, Bill Nye the Science Guy, education, streaming video
Those of you who do not know who Bill Nye the Science Guy! is will especially enjoy this video. In this streaming episode, Bill Nye the Science Guy explores the science behind genes (part 3). Basically, you can thank your parents for all those nice pairs of genes. Chromosomes are made up of sequences of genes, which are themselves made up of strands of DNA. The mutations in DNA during replication cause resulting changes within genes, which is the basis of evolution. [8:54].
grrlscientist | March 14, 2008tags: genetics, Bill Nye the Science Guy, education, streaming video
Those of you who do not know who Bill Nye the Science Guy! is will especially enjoy this video. In this streaming episode, Bill Nye the Science Guy explores the science behind genes (part 2). Basically, you can thank your parents for all those nice pairs of genes. Chromosomes are made up of sequences of genes, which are themselves made up of strands of DNA. The mutations in DNA during replication cause resulting changes within genes, which is the basis of evolution. The third and last part appears tomorrow morning. [6:17].
grrlscientist | March 13, 2008tags: genetics, Bill Nye the Science Guy, education, streaming video
Those of you who do not know who Bill Nye the Science Guy! is will especially enjoy this video. In this streaming episode, Bill Nye the Science Guy explores the science behind genes (part 1). Basically, you can thank your parents for all those nice pairs of genes. Chromosomes are made up of sequences of genes, which are themselves made up of strands of DNA. The mutations in DNA during replication cause resulting changes within genes, which is the basis of evolution. [7:53].