Introduction to Genetic Analysis 618

Introduction to Genetic Analysis 618 - 44200_19_p611-642...

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brates, and invertebrates. The results are remarkably con- sistent over species. About one-third of genes coding for proteins are detectably polymorphic at the protein level, and the average heterozygosity in a population over all loci sampled is about 10 percent. This means that scan- ning the genome in virtually any species would show that about 1 in every 10 genes in an individual is in het- erozygous condition for genetic variations that are re- Fected in the amino acid sequence of the proteins, and about one-third of all genes have two or more such al- leles segregating in any population. Thus the potential of variation for evolution is immense. The disadvantage of the electrophoretic technique is that it detects variation only in protein-coding regions of genes and misses the important changes in regulatory elements that underlie much of evolution of form and function. DNA structure and sequence polymorphism DNA analysis makes it possible to examine variation in genome structure among individuals and between species. There are three levels at which such studies can
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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.

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