Since the first human genome sequences were completed early in the first decade of this millennium, the genomes of many other individuals have been sequenced and published. With the rapid development of sequencing technologies, a human genome can be sequenced for less than $1,000.
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The human genome and its genes exemplify the characteristics of complex eukaryote genomes.
Comparisons of haplotypes of individuals with and without a particular genetic disease can identify loci associated with the disease.
Pharmacogenomics is the study of how an individual’s genome affects responses to drugs or other outside agents.
The following are just some of the interesting facts that sequencing of the human genome has brought to light:
Of the 3.2 billion bp in the haploid human genome, only an estimated 1.2 percent (about 21,000 genes) make up protein-
The average human gene has 27,000 bp. Gene sizes vary greatly, from about 1,000 bp to 2.4 million bp. Variation in gene size was expected given that human proteins (and RNAs) vary in size, from 100 to about 5,000 amino acids per polypeptide chain.
Most human genes have many introns. The “average” human gene has eight of them, with an average length of 3,300 bp.
About half of the genome is made up of transposons (see Table 17.6) and other highly repetitive sequences.
When the genomes of two unrelated individuals of the same species are compared, most of the sequence—
Genes are not evenly distributed over the genome. Chromosome 19 is packed densely with genes, whereas chromosome 8 has long stretches without coding regions. The Y chromosome has the fewest genes (about 230), and chromosome 1 has the most (about 3,000).
Media Clip 17.1 A Big Surprise from Genomics
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