A cross in Drosophila melanogaster involved the recessive X-linked genes for white eye (w), yellow body (y)., and cut wings (c). A wild-type tri-hybrid female was crossed with wild-type males and only the male offspring were tallied. On the basis of the results shown below, which of the choices shown best represents the genetic map of the three loci on the X-chromosome? Phenotype Male Offspring + yct 63 W ++ 60 w y ct 16 + + + 11 + + ct w y + + y + 247 w + ct 197

A cross in Drosophila melanogaster involved the recessive X-linked genes for white eye (w), yellow body (y)., and cut wings (c). A wild-type tri-hybrid female was crossed with wild-type males and only the male offspring were tallied. On the basis of the results shown below, which of the choices shown best represents the genetic map of the three loci on the X-chromosome? Phenotype Male Offspring + yct 63 W ++ 60 w y ct 16 + + + 11 + + ct w y + + y + 247 w + ct 197

Human Anatomy & Physiology (11th Edition)

11th Edition

ISBN:9780134580999

Author:Elaine N. Marieb, Katja N. Hoehn

Publisher:Elaine N. Marieb, Katja N. Hoehn

Chapter1: The Human Body: An Orientation

Section: Chapter Questions

Problem 1RQ: The correct sequence of levels forming the structural hierarchy is A. (a) organ, organ system,...

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Miniature wings (Xm) in Drosophila result from an X-linked allele that is recessive to the allele for long wings (X*). Give the genotypes of the parents in the following cross: Male parent Female parent Male offspring Female offspring 231 long, 250 miniature Long Long 560 long O male: Xm/Y and female X* /X* male: X* / Y and female Xm /x O male: X* /Y and female X* /X* male: Xm/Y and female Xm /x+
The wild-type (normal) fruit fly, Drosophila melanogaster, has straight wings and long bristles. Mutant strains have been isolated that have either curled wings or short bristles. The genes representing these two mutant traits are located on separate chromosomes. Carefully examine the data from the following five crosses shown below (running across both columns). (a) Identify each mutation as either dominant or recessive. In each case, indicate which crosses support your answer. (b) Assign gene symbols and, for each cross, determine the genotypes of the parents.
The mutant genes for vestigial wings and singed bristles are approximately 30 map units apart on chromosome II in Drosophila. Assume that a vestigial-winged female was mated to a singed-bristle male, and that the resulting F1 phenotypically wild type females were mated to vestigial singed males. Of 1000 offspring, which phenotype class would represent the product of crossing over between the genes, and how many would you expect? a) vestigial, 300 flies b) vestigial, 150 flies wild type, 300 flies d) singed, 150 flies e) vestigial, singed double mutants, 150 flies
Here are the results obtained by Bridges and Morgan for crossing over analysis between black, curved, purple, speck, star and vestigial genes, all on II chromosome of drosophila. - Draw the genetic map of chromosome II. Tested mutations black curved black purple black speck black star black vestigial curved purple curved speck curved star curved vestigial purple speck purple star purple vestigial speck star speck vestigial star vestigial Total nb of analyzed flies (T) 62 679 48 951 685 16 507 20 153 51 136 10 042 19 870 1 720 11 975 8 155 13 601 7 135 2 054 450 Nb of identified recombinant (R) 14 237 3 026 326 6 250 3 578 10 205 3 037 9 123 141 5 474 3 561 1 609 3 448 738 195 R/T ratio 0,2271 0,0618 0,4759 0,3786 0,1775 0,1996 0,3024 0,4591 0,0820 0,4571 0,4366 0,1183 0,4832 0,3592 0,4333
IN DROSOPHILA, AN X-LINKED RECESSIVE MUTATION, Xm CAUSES MINIATURE WINGS. LIST THE F₂ PHENOTYPIC RATIOS IF: A MINIATURE-WINGED FEMALE IS CROSSED WITH A NORMAL MALE AND A MINIATURE-WINGED MALE IS ● ● CROSSED WITH A NORMAL FEMALE. WHAT WOULD THE PHENOTYPIC RATIO FROM (A) BE IF THE MINIATURE- WINGED GENE WERE AUTOSOMAL? ASSUME IN ALL CASES THAT THE P1 INDIVIDUALS ARE TRUE-BREEDING.
In Drosophila, a female with three recessive traits, miniature wings, (m), ebony body (e) and rough eyes (r) were crossed with true-breeding wild-type males. In the F1, all offspring had wild-type phenotypes. F1 offspring were testcrossed to miniature, ebony, rough individuals and 1000 offspring were counted, shown in the table below. Determine the genotypes of the P1 and F1 parents. Determine the sequence of the three genes and the map distance between them. Are there more or fewer double crossovers than expected? Calculate the interference. Phenotype Offspring m e r 310 + + + 284 + e r 150 m + + 156 m + r 45 + e + 32 m e + 8 + + r 15 Total 1000
Two recessive traits in mice—droopy ears and flaky tail—arecaused by genes that are located 6 mu apart on the same chromosome.A true-breeding mouse with normal ears (De) and a flaky tail ( ft)was crossed to a true-breeding mouse with droopy ears (de) and anormal tail (Ft). The F1 offspring were then crossed to mice withdroopy ears and flaky tails. If this testcross produced 100 offspring,Make a drawing. Predict the outcome. Make a calculation.
You design Drosophila crosses to provide recombinationdata for gene a, which is located on the chromosome shownin Figure 15.12. Gene a has recombination frequencies of14% with the vestigial wing locus and 26% with the browneye locus. Approximately where is a located along thechromosome?
Vestigial wing is a recessive autosomal mutation in the fruit fly Drosophila melanogaster. Wild-type flies have red eyes, but another mutation, an X-linked recessive mutation causes white eyes. You cross a parental generation of males with vestigial wings with females that have white eyes. 1) What phenotypic ratio would you expect in the F1 generation from such a cross? What phenotypes do you observe in these flies? (e.g. males with red eyes and wild-type wings). 2) What phenotypic ratio would you expect in the F2 generation? What phenotypes do you observe in these flies?
Consider the following crosses in Drosophila. The two traits being investigated involve eye color and the presence or absence of wing crossveins. The outcomes of four crosses are shown below.›
Consider the first category of test-cross offspring shown in figure 8.2 (+b, LS). Consider also that the parents of the heterozygous female flies in the test cross had the following genotypes: bb, SS, and +, LL. A. What would be the physical phenotype of these flies? B. If PC was conducted with the DNA of one of these flies using the primers for the molecular marker, what would be the appearance of the bands on an electrophoresis gel with the PC products? C. If the gene for black body and the locus for the molecular marker (L long or S short) were unlinked, what proportion of the test-cross progeny would be black flies that are heterozygous for the molecular marker? What proportion would be flies with normal body color, which are homozygous for one form of the molecular marker? D. If the gene for black body and the locus for the molecular marker were linked, how would the proportion of flies be different?
The phenotype of crooked wings (cw) in Drosophila melanogaster is caused by a recessive mutant gene that independently assorts with a recessive mutant gene for hairy (h) body. Assume that a cross is made between a fly with normal wings and a hairy body and a fly with crooked wings and normal body hair. All F1 flies from this cross were wild-type, and these flies were crossed among each other to produce 288 F2 offspring. Which phenotypes would you expect among the offspring in the F2 generation, and how many of each phenotype would you expect?