biological homology

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DNA is the bedrock of our genetic identity. DNA encodes the physical and mental traits in our genes are it is generally unchanging and the same in all cells. There are ‘epigenetic’ aspects, still somewhat puzzling, that appear to carry over between generations, which are not due to the modification of DNA sequence. (Other posts have explored epigenetics.) But DNA sequence is the default molecule as carrier of our genetic identity.

Although the DNA in our cells is largely unchanging and the same in every cell, neither of those features is strictly true.… Read the rest “the goldilocks zone: Mutation, Cancer, and Evolution”

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Some people have a hard time keeping to the conventional clock. They strongly prefer to sleep and stay up late. Some people show the opposite behaviour; they wake up very early, but are ready for bed well before the late evening news. Although there may be exceptions (teenagers and jazz musicians come to mind), both kinds of behaviour are often related to a changed circadian rhythm. Late sleepers are referred to as “delayed phase” in their circadian rhythm, while those who are exceptionally early to bed – early to rise are said to have “Familial Advanced Sleep Phase Syndrome” (FASPS).… Read the rest “Circadian Rhythm II – Us”