Concept explainers
The tiny frog paedophryne amauensis was discovered by researchers purposefully searching for the source of an unusual sound, but sometimes similarity between two species can lead scientists to accidental discoveries. A previously unknown species of wild cat was inadvertently discovered by researchers who were sequencing the DNA of a house cat-sized South American wild cat called the tigrina. The DNA analysis revealed that many alleles found in the supposed tigrinas living in northeastern Brazil are not shared with other tigrinas. This finding suggested that the northeastern cats do not interbreed with other tigrinas and are therefore a different species. What prevents the two species from interbreeding?
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Biology: Life on Earth with Physiology (11th Edition)
- In 1979, bones found outside Ekaterinburg, Russia, were shown to be those of Tsar Nicholas and his family, who were executed in 1918 by a Bolshevik firing squad in the Russian Revolution . To prove that the skeletons were those of the royal family, mtDNA was extracted from the bone samples, amplified by PCR, and compared with mtDNA from living relatives of the tsar’s family. Q. Mitochondrial DNA from which living relatives would provide useful information for verifying that the skeletons were those of the royal family?arrow_forwardYou are a researcher studying birds in an Indonesian rainforest. You have just discovered two new species whose beaks are markedly different, which you have named Laetiphonia orthorhynchus and Laetiphonia rhamphis. In particular, the beaks of L. orthorhynchus are very long, straight and pointed, whereas L. rhamphis have beaks that are quite short, wide and curved downwards. In further studies, you find that the same gene codes for beak shape in both species. In your own words, explain at least two ways that changes in gene expression could result in the differences you observe between these two species. Make sure to be specific in how your explanation applies to the bird species in this example.arrow_forwardLion populations are found all over sub- Saharan africa. How do the sequences above reinforce or contradict the idea that populations of lions who are genetically similar live in the same geographic area?arrow_forward
- Since nucleotide sequences are more variable than amino acid sequences, you’ll use GAPDH nucleotide sequences to compare across the six taxa you’re analyzing. Suppose that you used BLAST to align all possible pairs of GAPDH sequences among lancelet, lamprey, bass, frog, turtle, and leopard. You would be able to construct the following table showing the percent similarity values across all six taxa. Leopard Turtle Frog Bass Lamprey Lancelet Leopard 100% 83% 80% 81% 76% 74% Turtle – 100% 79% 79% 74% 72% Frog – – 100% 79% 74% 71% Bass – – – 100% 77% 74% Lamprey – – – – 100% 73% Lancelet – – – – – 100% Now you can use this data (similarly to how you used the data in the character table) to build a phylogenetic tree. The distance between species in a tree is directly related to the amount of similarity between their gene sequences. For instance, two species will be closer together if the amount of similarity is high, or far apart if the amount of similarity is low. Which…arrow_forwardIn the United States, the rare red wolf (Canis lupus) has been known to hybridize with coyotes (Canis latrans), which are much more numerous. Although red wolves and coyotes differ in terms of morphology, DNA, and behavior, genetic evidence suggests that living red wolf individuals are actually hybrids. Red wolves are designated as an endangered species and hence receive legal protection under the Endangered Species Act. Some people think that their endangered status should be withdrawn because the remaining red wolves are hybrids, not members of a "pure" species. Do you agree? Why or why not?arrow_forwardIn addition to physical traits, gene sequences can be used when comparing related species. Instead of looking for the presence or absence of a specific gene, you would look at the percent similarity between the same gene in two or more species. Therefore, it is important to select a gene that contains a similar DNA gene sequence in each of the species being compared. Certain genes are involved in processes that are required for basic cellular function. As these processes are critical to cell function, the genes that regulate them are highly conserved, meaning that they have remained essentially unchanged over time. Glycolysis is one such process that is critical for cellular metabolism. Glycolysis involves converting glucose into pyruvate in order to generate ATP, the energy currency of the cell. Because glycolysis is an essential process for all species, the genes involved are therefore highly conserved. You will be looking at similarities among different taxa of the highly conserved…arrow_forward
- DNA profiling has been used to verify pedigrees of valuable animals such as show dogs, racing greyhounds, and thoroughbred horses. However, the technology is much harder to apply in these cases than it is in forensic applications for humans. In particular, many more DNA markers must be examined in domesticated animals to stablish the identity or close familial relationship of two DNA samples. Why would you need to look at more polymorphic loci in these animals than you would in humans?arrow_forwardAn hypothesis for the extinction of the dinosaurs is that the earth had been hit by a gigantic meteor that caused the death of those big reptiles. In that case the entire genetic pool of those animals has been destroyed, invalidating the Hardy-Weinberg equilibrium. In Genetics what is this type of gene frequency change called?arrow_forwardIn a study of a muscle disorder, several affected families exhibitedvision problems, muscle weakness, and deafness (M. Zeviani et al. 1990.American Journal of Human Genetics 47:904–914). Analysis of themtDNA from affected members of these families revealed that largenumbers of their mtDNA molecules possessed deletions of varyinglengths. Different members of the same family and even differentmitochondria from the same person possessed deletions of differentsizes, so the underlying defect appeared to be a tendency for the mtDNAof affected persons to have deletions. A pedigree of one of the familiesstudied is shown below. The researchers concluded that this disorder isinherited as an autosomal dominant trait, and they mapped the diseasecausinggene to a position on chromosome 10 in the nucleus.a. What characteristics of the pedigree rule out inheritance of a traitencoded by a gene in the mtDNA as the cause of this disorder?b. Explain how a mutation in a nuclear gene might lead to deletions…arrow_forward
- If myoglobin is found in all chordates, urochordates, and cephalochordates, b-globin is found in all vertebrates, a-globin in all ostracoderm descendants, z-globin in all gnathostomes, e-globin in all viviparous mammals, and d-globin in all eutherian mammals, then the most recent globin gene must be: myoglobin, found only in descendants of the chordates, urochordates, and cephalochordates zeta-globin (z-globin), found only in descendants of the ancestral gnathostome fishes epsilon-globin (e-globin), found only in descendants of the ancestral marsupials beta-globin (b-globin), found only in descendants of the ancestral vertebrates delta-globin (g-globin), found only in descendants of the ancestral eutheriansarrow_forwardSuppose 40 percent of people living in a remote, isolated mountain village can taste phenylthiocarbamide (PTC) and must, therefore, have at least one copy of the dominant PTC taster allele. If this population conforms to Hardy-Weinberg expectations for this gene, what percentage of the population must be heterozygous for this trait? Please explain how you got your answer.arrow_forwardIf you had the ability to do gene editing with ONE gene for the betterment of human kind, which one would you choose, and why? Assume you could either change an abnormal allele associated with a disease, such as the cystin gene associated with Cystic Fibrosis to its normal wild type, or add a pre-existing human allele to a genome.arrow_forward
- Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage Learning