In Mendel's experiments with peas, one single locus was responsible for determining whether a plant would be tall or short. Similarly, different alleles of a single locus in humans, for example the FGFR3 locus, can make a person either exceptionally tall or to be a dwarf. Yet, we know that hundreds of genes are responsible for determining height among the normal population. Briefly explain in your own words why sometimes one locus can explain the difference between very tall/short while at other times it is hundreds of loci that determine height

In Mendel's experiments with peas, one single locus was responsible for determining whether a plant would be tall or short. Similarly, different alleles of a single locus in humans, for example the FGFR3 locus, can make a person either exceptionally tall or to be a dwarf. Yet, we know that hundreds of genes are responsible for determining height among the normal population. Briefly explain in your own words why sometimes one locus can explain the difference between very tall/short while at other times it is hundreds of loci that determine height

Human Heredity: Principles and Issues (MindTap Course List)

11th Edition

ISBN:9781305251052

Author:Michael Cummings

Publisher:Michael Cummings

Chapter5: The Inheritance Of Complex Traits

Section: Chapter Questions

Problem 2QP: The text outlines some of the problems Frederick William I encountered in his attempt to breed tall...

See similar textbooks

Similar questions

For Mendelian inheritance, the nuclear genotype (i.e., the allelesfound on chromosomes in the cell nucleus) directly influences anoffspring’s traits. In contrast, for non-Mendelian inheritance patterns, the offspring’s phenotype cannot be reliably predicted solelyfrom its genotype. For the following traits, what do you need toknow to predict the phenotypic outcome?A. Dwarfism due to a mutant Igf2 alleleB. Snail coiling directionC. Leber hereditary optic neuropathy
. In 1919, Calvin Bridges began studying an X-linkedrecessive mutation causing eosin-colored eyes inDrosophila. Within an otherwise true-breedingculture of eosin-eyed flies, he noticed rare variantsthat had much lighter cream-colored eyes. By intercrossing these variants, he was able to make a truebreeding cream-eyed stock. Bridges now crossedmales from this cream-eyed stock with true-breedingwild-type females. All the F1 progeny had red (wildtype) eyes. When F1 flies were intercrossed, the F2progeny were 104 females with red eyes, 52 maleswith red eyes, 44 males with eosin eyes, and14 males with cream eyes. Assume that thesenumbers represent an 8:4:3:1 ratio.a. Formulate a hypothesis to explain the F1 and F2results, assigning phenotypes to all possiblegenotypes.b. What do you predict in the F1 and F2 generations if the parental cross is between truebreeding eosin-eyed males and true-breedingcream-eyed females?c. What do you predict in the F1 and F2 generationsif the parental cross is…
Mendel studied a tall variety of pea plants with stemsthat are 20 cm long and a dwarf variety with stems thatare only 12 cm long.a. Under blending theory, how long would you expectthe stems of first and second hybrids to be?b. Under Mendelian rules and assuming stem lengthis controlled by a single gene, what would you expectto observe in the second-generation hybrids if all thefirst-generation hybrids were tall?
Two alleles at one locus produce three distinctphenotypes. Two alleles of two genes lead tofive distinct phenotypes. Two alleles of six geneslead to 13 distinct phenotypes. (These statementsassume that the alleles at any one locus arecodominant or incompletely dominant andthat each gene makes an equal contributionto the phenotype.)a. Derive a formula to express this relationship. (Letn equal the number of genes.)b. Each of the most extreme phenotypes for a traitdetermined by two alleles at one locus are foundin a proportion of 1/4 in the F2 generation. If twoalleles of two genes determine the trait, each extreme phenotype will be present in the F2 as 1/16of the population.In common wheat (Triticum aestivum),kernel color varies from red to white andthe genes controlling the color act additively,that is, alleles for each gene are incompletelydominant and each gene contributes equallyto the color. A true-breeding red variety iscrossed to a true-breeding white variety, and1/256 of the F2…
In Figure 1-6, the students have 1 of 15 different heights,plus there are two height classes (4′11″ and 5′ 0″) forwhich there are no observed students. That is a total of17 height classes. If a single Mendelian gene can account for only two classes of a trait (such as purple orwhite flowers), how many Mendelian genes would beminimally required to explain the observation of 17height classes?
This problem examines possible biochemical explanations for variations of Mendel’s 9:3:3:1 ratio. Exceptwhere indicated, compounds 1, 2, 3, and 4 have different colors, as do mixtures of these compounds. Aand B are enzymes that catalyze the indicated steps ofthe pathway. Alleles A and B specify functional enzymes A and B, respectively; these are completelydominant to alleles a and b, which do not specify anyof the corresponding enzyme. If functional enzyme ispresent, assume that the compound to the left of thearrow is converted completely to the compound to theright of the arrow. For each pathway, what phenotypicratios would you expect among the progeny of a dihybrid cross of the form Aa Bb × Aa Bb?a. Independent pathwaysCompound 4Compound 2Compound 3Compound 1Enz AEnz Bb. Redundant pathwaysCompound 1 Compound 2Enz BEnz Ac. Sequential pathwayCompound 1 Compound 2 Compound 3Enz A Enz Bd. Enzymes A and B both needed to catalyze the reaction indicated.Compound 1 Compound 2
For all seven characters described in the data of Mendel allowed the F2 plants to self-fertilize. He found that whenF2 plants with recessive traits were crossed to each other, theyalways bred true. However, when F2 plants with dominant traitswere crossed, some bred true but others did not. A summary ofMendel’s results is shown to the right When considering the data in this table, keep in mind that theydescribe the characteristics of the F2 generation parents that haddisplayed a dominant phenotype. These data were deduced byanalyzing the outcome of the F3 generation. Based on Mendel’slaws, explain why the ratios were approximately 1:2
Many beautiful varieties of roses have been produced, particularlyin the last few decades. These newer varieties often have verystriking and showy flowers, making them desirable as horticulturalspecimens. However, breeders and novices alike have noticed thatsome of these newer varieties are not very fragrant compared withthe older, more traditional varieties. From a genetic point of view,suggest an explanation why some of these newer varieties withsuperb flowers are not as fragrant.
Piebald spotting is a condition found in humans inwhich there are patches of skin that lack pigmentation. The condition results from the inability ofpigment-producing cells to migrate properly duringdevelopment. Two adults with piebald spotting haveone child who has this trait and a second child withnormal skin pigmentation.a. Is the piebald spotting trait dominant or recessive?What information led you to this answer?b. What are the genotypes of the parents?
In individuals affected by cystic fibrosis, salt crystals may appear afterperspiration dries up. In addition, the disease causes respiratory disorderswhich can be both debilitating and lethal. It occurs in individuals homozygousfor the recessive gene. Two normal parents had a daughter with thesymptoms of this disease, and a normal son who marries a normal womanwith an afflicted A test (salt concentration in perspiration of heterozygotes ishigher than normal) disclosed that both are indeed carriers of the gene. If thefirst child born to the mating in (b) was defective, what is the probability thatthe 2nd child would also be defective?Express answer in fraction form
The text outlines some of the problems Frederick William I encountered in his attempt to breed tall Potsdam Guards. a. Why were the results he obtained so different from those obtained by Mendel with short and tall pea plants? b. Why were most of the children shorter than their tall parents?
The Online Mendelian Inheritancein Man (OMIM) databaseis a catalog of human genesand human disorders that are inheritedin a Mendelian manner. Genetic disordersthat arise from major chromosomalaberrations, such as monosomyor trisomy(the loss of a chromosome orthe presence of a superfluous chromosome,respectively), are not included.The OMIM database, updated daily, is aversion of the book Mendelian Inheritancein Man, conceived and edited by Dr. VictorMcKusick of Johns Hopkins University,until he passed in 2008.The OMIM entries provide links to awealth of information, including DNAand protein sequences, chromosomalmaps, disease descriptions, and relevantscientific publications. In this exercise,you will explore OMIM to answer questionsabout the recessive human diseasesickle-cell anemia and other Mendelianinherited disorders.Exercise I – Sickle-Cell AnemiaIn this chapter, you were introduced torecessive and dominant human traits.You will now discover more about sicklecellanemia as an…