Word: chromatin
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...Specifically, there is a change in chromatin structure so that the DNA collapses and forms a crystal matrix, inhibiting gene expression. Instead of the dormant organism using energy to sense the environment, it acts as a biophysical switch—when environmental conditions change, the chromatin relaxes and gene expression can resume...
...will have other master regulatory genes deactivated. ES cells have the potential to become any other type of tissue cell, but how they do so is not clear and is essential if treatments are to be developed from research. This process of activating master regulatory genes is facilitated by chromatin, a histone protein structure that contains a cell’s DNA. If there is a methyl group anchored in a certain place on one histone protein, the gene nearby is activated (known as the K4 state). Conversely, if the methyl group attaches itself to another part of the protein...
Died. Alfred Ezra Mirsky, 73, distinguished biochemist at New York City's Rockefeller University who in the 1940s helped spark the infant field of molecular biology by devising a technique for isolating the genetic material chromatin in the cells of animals; of a heart attack; in Manhattan...
...grown into tiny embryos but had not yet become implanted in the uterine wall. They placed each embryo under a microscope, cut a tiny slit in its surrounding membrane and drew out several hundred cells with a suction pipette. The cells were then examined for the presence of sex chromatin, a substance found only in female cells. Separated into male and female groups, the embryos were next placed in a culture medium, a laboratory equivalent of a hospital recovery room...
From that same sample, the Albany researchers have also learned to determine an unborn infant's sex. Micro scopic examination of carefully cultivated slides, they discovered, reveals the presence or absense of the sex-chromatin body that determines femininity. And in every case in which the sample was adequate, not only did all the researchers agree on their prediction, but in every case they were correct. Enthusiastically they reported that there is no reason why the test should not always be 100% accurate. Then they quickly added a word of caution. Since obtaining a sample of the amniotic fluid...