Parent chromosomes

Crossover, which is also called recombijiation, follows the idea that aji offspring in natiu c always holds genes from both its parents. Accordingly, the genetic crossover operator takes parts of two parent chromosomes to create a new offspring. 

Figure 2 Genetic operators used to create a population of children chromosomes from a population of parent chromosomes, (a) Single-point mutation. A gene to he mutated is selected at random, and its value is modified, (b) One-point crossover. The crossover point is selected randomly, and the genes are exchanged between the two parents. Two children are created, each having genes from both parents.

Watson and Crick (see Volume 1) immediately saw the relationship of the double helix to genetic replication. They proposed that each strand of the chromosome serves as a template to specify a new, complementary DNA strand. A template is a pattern for making something DNA acts as a template because each strand specifies the new daughter strand by base-pairing. This template feature makes DNA replication semiconservative after replication, each daughter chromosome has one strand of newly synthesized DNA and one strand of DNA from the parental chromosome. See Figure 8-6. 

Fig. 6. Physical detection of reciprocal translocations. The chromosomes shown are identical to those in Fig. S. Vertical arrows represent recognition sites for a single restriction enzyme horizontal arrows correspond to synthetic oligonucleotide primers and lines below the chromosomes indicate the sizes of restriction or PCR fragments. In (A), the alteration in restriction fragment size as a result of exchange is illustrated. Such alterations can be detected by Southern analysis using the duplicated sequence as a probe. In (B), the production of a PCR product from one of the exchange chromosomes is illustrated. Neither parental chromosome directs synthesis of a PCR product.

The answer is c. (Murray, pp 812-828. Scriver, pp 3-45. Sack, pp 57-76. Wilson, pp 123-149.) Fluorescent in situ hybridization (FISH) analysis is a technique in which molecular probes that are specific for individual chromosomes or chromosomal regions are used to identify these regions. FISH probes frequently identify chromosomal regions that are submicro-scopic and therefore may be useful when standard karyotypic analysis is normal. In this case, the fact that only one signal is present, despite the fact that there are two number 22 chromosomes, indicates that a submicro-scopic deletion has occurred. The parental chromosome of origin cannot be determined using this technique unless that parent also carries a similar deletion and his or her chromosomes are evaluated. 

A FIGURE 21-1 Summary of major events in the eukaryotic cell cycle and the fate of a single parental chromosome. 

Create new chromosomes by mating current chromosomes apply mutation and recombination as the parent chromosomes mate. 

The crossover operation is a random process with a probability of crossover, which breeds a pair of child chromosomes from a pair of parental chromosomes. The typical probability of the crossover operator is between 0.6 and 1.0. A large number of crossover operators have been proposed (Poon and Carter, 1995). Uniform order crossover (Davis, 1991) is cotrunonly utilized because it has the advantage of preserving the position of some genes and the relative sequence of the rest. It is adopted in this research and its procedure is as follows ... 

Step 4 Evaluate the fimess, [Pg.95]

Fill some positions with the offspring chromosome by copying corresponding elements of the first parent chromosome associated with a 1 in the decision string. That is to say, the same components appear in the same positions in the offspring chromosome as they do in the first parent chromosome. 

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