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Redefining Reality - The Intellectual Implications of Modern Science

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Darwin posited that children look like their parents but never<br />

understood the mechanism. Twentieth-century biology showed that<br />

the mechanism <strong>of</strong> inheritance is the transfer <strong>of</strong> genetic material<br />

located on chromosomes in the cell’s nucleus. <strong>The</strong> genes are made up <strong>of</strong><br />

DNA, which codes for protein production that gives rise to the observable<br />

properties. This discovery allowed us to understand how certain illnesses<br />

have their roots in a person’s DNA and leads us to ask whether it would be<br />

good for individuals and the species to breed out these genetic problems, that<br />

is, whether eugenics is morally necessary or necessarily immoral.<br />

<br />

<br />

<br />

regularities in inheritance. Mendel showed that some traits are<br />

dominant, others are recessive, and the passing on <strong>of</strong> traits can<br />

be modeled mathematically. But he was unable to discover the<br />

<br />

the reproductive process.<br />

<br />

Around the same time that Darwin and Mendel were doing their<br />

work, the focus <strong>of</strong> biology turned to the role <strong>of</strong> the nucleus in cell<br />

division, especially in fertilized eggs. One structure in the nucleus,<br />

the chromosomes, seemed a good candidate for the cellular “coins”<br />

biologists sought for three reasons:<br />

First, the number <strong>of</strong> chromosomes in a cell nucleus was the<br />

same in all the cells <strong>of</strong> every organism <strong>of</strong> a given species but<br />

different for different species.<br />

<br />

Second, the chromosomes were two seemingly identical<br />

strands that were tangled together; during cell division in<br />

most cells, they untangled themselves, with each new nucleus<br />

getting one <strong>of</strong> them.<br />

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