Some retrotransposons and retroviruses integrate preferentially into regions of the chromosome that are packaged in euchromatin and are also located outside the coding regions of genes that contain information for making a protein
Why might these mobile genetic elements have evolved this strategy?
The most evolutionarily successful mobile genetic elements are those that are best at reproducing themselves. To increase the number of copies of a particular element, the element must meet two criteria: (1) it must not kill its host, and (2) it must maximize its ability to continue reproducing. If an element inserts into the coding region of a gene, it might disable the gene and thereby confer a selective disadvantage in the reproduction or survival of its host. Thus, elements that devised a way to avoid insertion into coding regions were probably better able to increase their copy number throughout the human population. If an element inserts into a heterochromatic region of a chromosome, its genes may not be expressed and therefore it may become immobile. Elements that devised a way to direct insertion into euchromatin would be more likely to maintain mobility and thereby increase their copy number over time.
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The hypothesis that mitochondria and chloroplasts evolved as a result of a close relationship with another cell is known as ________
a. endosymbiosis b. thermodynamics c. parasitism d. the Big Bang theory e. evolution
Genetic mapping involves the idea of mapping the genes linearly, based on what concept?
a. Genes that are located close together will recombine less often than those located far apart. b. Genes mutate at a constant rate which results in a mutation clock that can be used to track time. c. Genes can be mapped based on how often the cell divides because mistakes are made during mitosis. d. Genes that are recessive mutate more often than dominant genes.
What animals are considered to be sessile?
a. Sponges b. Mussels c. Barnacles d. Corals
In analyzing data for crosses involving one gene, Mendel discovered that alleles are discrete entities, and that they are separated during formation of gametes. This was the basis of Mendel's law of ________
Fill in the blank with correct word.