Chapter 15 notes - Chapter 15 notes Phenotype of an...

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Chapter 15 notes Phenotype of an organism can be affected by small-scale changes involving individual genes.  Random mutation is the source of all new alleles that leads to new phenotype traits. Other things that can affect phenotype are: Large-scale chromosomal change (leads to miscarriage) Physical and Chemical disturbance Errors in meiosis These all can damage the chromosomes in major ways or alter their number in a cell. The  individual born with these defects usually has some sort of disorder. Abnormal Chromosome Number Non-disjunction:  An error in meiosis or mitosis in which members of a pair of homologous  chromosomes or a pair of sister chromatids fail to separate properly from each other. In these cases, one gamete receives two of the same type of chromosome and another gamete  receives no copy (others are usually distributed normally). Aneuploidy: A chromosomal aberration in which one or more chromosomes are present in extra 
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This note was uploaded on 09/01/2009 for the course BIOLOGY biol1 taught by Professor Turkey during the Spring '99 term at Abu Dhabi University.

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Chapter 15 notes - Chapter 15 notes Phenotype of an...

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