Concept explainers
Canine hip dysplasia is a quantitative trait that continues to affect most large breeds of dogs in spite of approximately 40 years of effort to reduce the impact of this condition. Breeders and veterinarians rely on radiographic and universal registries to facilitate the development of breeding schemes for reducing its incidence. Data [Wood and Lakhani (2003). Vet. Rec. 152:69–72] indicate that there is a “month-of-birth” effect on hip dysplasia in Labrador retrievers and Gordon setters, whereby the frequency and extent of expression of this disorder vary depending on the time of year dogs are born. Speculate on how breeders attempt to “select” out this disorder and what the month-of-birth phenomenon indicates about the expression of polygenic traits.
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Concepts of Genetics (12th Edition)
- Briefly describe the polygenic threshold theory. How polygenic traits can be genetically determined? What are major factors affecting gene frequencies? How the Hardy-Weinberg relationship can be used in genetic counseling? Is it useful for genetic risk prediction?arrow_forwardNon-additive genetic factors make children less resemble their parents true and false (with explain)arrow_forwardAn individual with a form of red-green color blindness processes a genetically inherited trait that makes it difficult to distinguish red and green color hues. Red-green color blindness tends to skin generations and it is found much more often in men than in women. If a man who was normal and a woman who is a carrier for this form of colorblindness have a child, when the probability that the child will be red-green colorbind is: -0% -25% -50% -75% -100%arrow_forward
- Dizygotic twinning often runs in families, and its frequency varies among ethnic groups, whereas monozygotic twinning rarely runs in families, and its frequency is quite constant among ethnic groups. These observations have been interpreted as evidence of a genetic basis for variation in dizygotic twinning but little genetic basis for variation in monozygotic twinning. Can you suggest a possible reason for these differences in the genetic tendencies toward dizygotic and monozygotic twinning?arrow_forwardImagine that genetic technology advances to the point where the genetic profile of an individual can be easily obtained, and that we have a full understanding of how genes interact to influence our health. Based on this genetic information alone, how reliably do you think we would be able to predict a person's chance of getting a specific disease? Where do you think this type of genetic profiling would lead with respect to selection of offspring or genetic superiority?arrow_forwardin considering the interaction of multiple genes involved in complex traits and interaction with the environmental factors what does the organisms genotype represent? What does the phenotype represent? What does the environment have to do with it?arrow_forward
- For the odds ratio and relative risk, what is the importance of the number 1?arrow_forwardHow does heritability differ between major trait categories such as morphology, life history, behavior, and physiology? Which trait types are generally most heritable and which are least heritable?arrow_forwardAccording to Amar J. S. Klar, is there a such thing as “left handedness”? What is the preferred term? Describe how the genetics works, according to his hypothesis. What are the alleles, and which combinations of alleles make for which type of hand use?arrow_forward
- What role would twin and adoption studies play in selecting a model for determining whether attendance at medical school is a heritable trait? What heritability values would make you take the study to the next level?arrow_forwardQTL mapping and GWA (association) mapping are two different methods used to identify genes that affect complex traits. For each of the following statements, choosewhether it applies to QTL mapping, association mapping, or both.whether it applies to QTL mapping, association mapping, or both.arrow_forwardThe classical twin study is established as the definitive study design for investigating the relative importance of genetic and environmental factors to traits and diseases in human population. Monozygotic (identical) twins share all of their genes, while Dizygotic(fraternal) twins share only about 50 percent of them, the same as non-twin siblings. If a researcher compares the similarity between sets of identical twins to that of fraternal twins for a particular trait, then any excess likeness between the identical twins should be due to genes rather than environment. Write an information leaflet evaluating the benefits and dilemmas in the use of human twin studies to investigate the causes of variation.arrow_forward
- Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage LearningConcepts of BiologyBiologyISBN:9781938168116Author:Samantha Fowler, Rebecca Roush, James WisePublisher:OpenStax College