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Unformatted text preview: 44200_03_p73-114 3/3/04 1:48 PM Page 99 3.4 Chromosome behavior and inheritance patterns in eukaryotes 99 DNA replication to form chromatids
Chromatid formation Homozygous diploid b / b DNA replication b b b b b b
Heterozygous diploid b + / b b b b b b b b b b b b Homozygous diploid b / b b b b b b b b Haploid b + b b b b Haploid b b b b b Figure 3-36 Chromatid formation and the underlying DNA replication. Left: Each chromosome
divides longitudinally into two chromatids; (right) at the molecular level, the single DNA molecule of each chromosome replicates, producing two DNA molecules, one for each chromatid. Also shown are various combinations of a gene with normal allele b and mutant form b, caused by a change of a single base pair from GC to AT. Notice that at the DNA level the two chromatids produced when a chromosome replicates are always identical with each other and with the original chromosome. ...
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