Chat with AIExam 8: The History in Our Genes
If a biologist wanted to associate each node of a phylogenetic tree with a statistical measure of support for a particular grouping, what is one method she could employ?
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VerifiedC
A woman who carries one G variant and one T variant of the BRCA1 gene would pass the T variant on to approximately how many of her children?
(33) VerifiedC
Please explain why the average rate of evolution differs between introns and exons, and why this is important for choosing genetic markers to be used in phylogeny construction.
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Answered by Examlex AI CopilotThe average rate of evolution differs between introns and exons due to their different functions and selective pressures. Exons are the coding regions of genes and are under strong selective pressure to maintain the correct amino acid sequence for protein function. As a result, exons tend to evolve more slowly and are more conserved across species. In contrast, introns are non-coding regions and are generally under less selective pressure, allowing for more rapid evolution and greater sequence divergence between species.
This difference in evolutionary rates is important for choosing genetic markers for phylogeny construction because markers with different rates of evolution can provide different levels of resolution for studying evolutionary relationships. Exons, with their slower rate of evolution, are useful for studying deeper evolutionary relationships between distantly related species. In contrast, introns, with their faster rate of evolution, are more useful for studying more recent evolutionary events and relationships between closely related species.
By understanding the differences in evolutionary rates between introns and exons, researchers can choose the most appropriate genetic markers for their phylogenetic studies, allowing for more accurate and informative reconstructions of evolutionary relationships among species.
You are studying the relationships among a group of ten cichlid fishes that have speciated very recently (say, the last 5000 years). Would you choose to use intron or exon sequences in your phylogenetic analysis? Explain your answer.
(28) Describe what information can be gleaned from gene trees created from within population sampling compared to. gene trees created from sampling individuals from different populations or species.
(40) Which of the following is supported by molecular phylogenetic studies?
(33) What mechanisms can create a mismatch between the history of genes and the history of species?
(35) A substitution that changes one of the first two bases in a codon (e.g., AGT) is called a _______ mutation and will ______.
(26) Maximum likelihood phylogenetic construction methods differ from distance methods in that
(30) Which of the following is a mechanism that bacteria have for increasing their genome size?
(32) A neutrally evolving allele in a population of a constant size is expected to have
(39) Please explain why homoplasy is particularly problematic in the construction of molecular phylogenies from DNA sequence data.
(41) Which of the following phylogenetic patterns supports the hypothesis that a disease was transmitted between partners?
(40) Why would bacteria that live in hosts have smaller genomes than free-living bacteria?
(36) FST estimates close to zero would suggest that a population
(33) Phylogenetic studies of HIV-1 emergence that used molecular clock estimates demonstrate that:
(30) Which of the following statements is true about mitochondrial DNA?
(39) Please contrast the "out of Africa" model of human evolution with the "multiregional" model.
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