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Unformatted text preview: 76 Chapter 3 • The Chromosomal Basis of Inheritance behavior of chromosomes at meiosis. Consider: genes are in pairs (so are chromosomes); the alleles of a gene seg- regate equally into gametes (so do the members of a pair of homologous chromosomes); different genes act inde- pendently (so do different chromosome pairs). Both in- vestigators reached the same conclusion, which was that the parallel behavior of genes and chromosomes strongly suggests that genes are located on chromosomes. It is worth considering some of the objections raised to the Sutton-Boveri theory. For example, at the time, chromosomes could not be detected in interphase (the stage between cell divisions). Boveri had to make some very detailed studies of chromosome position before and after interphase before he could argue persuasively that chromosomes retain their physical integrity through interphase, even though they are cytologically invisible at that time. It was also pointed out that, in some organisms, several different pairs of chromosomes look alike, making it impossible to say from visual observation that they are not all pairing randomly, whereas Mendel’s laws absolutely require the orderly pairing and segrega-...
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This note was uploaded on 01/10/2011 for the course BIOL BIOL taught by Professor Johnson during the Spring '08 term at Aberystwyth University.
- Spring '08