Concept explainers
Two diploid species of closely related frogs, which we will call species A and species B, were analyzed with regard to the genes that encode an enzyme called hexokinase. Species A has two distinct copies of this gene: A1 and A2. In other words, this diploid species is A1A1 A2A2. Species B has three copies of the hexokinase gene, which we will call B1, B2, and B3. A diploid individual of species B would be B1B1 B2B2 B3B3. These hexokinase genes from the two species were subjected to DNA sequencing, and the percentage of sequence identity was compared among these genes. The results are shown here.
Percentage of DNA Sequence Identity
A1 | A2 | B1 | B2 | B3 | |
A1 | 100 | 62 | 54 | 94 | 53 |
A2 | 62 | 100 | 91 | 49 | 92 |
B1 | 54 | 91 | 100 | 67 | 90 |
B2 | 94 | 49 | 67 | 100 | 64 |
B3 | 53 | 92 | 90 | 64 | 100 |
If we assume that hexokinase genes were never lost in the evolution of these frog species, how many distinct hexokinase genes do you think there were in the most recent ancestor that preceded the divergence of these two species? Explain your answer. Also explain why species B has three distinct copies of this gene, whereas species A has only two.
Want to see the full answer?
Check out a sample textbook solutionChapter 29 Solutions
Genetics: Analysis and Principles
- For a haploid fungus, the starting point in the biosynthesis of the amino acid arginine is Compound X, which is always present in and absorbed from the environment. The arginine biosynthetic pathway is: Enzyme A Enzyme B Enzyme Ç Compound X It is know that genes encoding enzymes A and C are on two different chromosomes. Compound Y Compound Z- Arginine A mutant strain of genotype a (lacking only enzyme A) is crossed to a mutant strain of genotype c (lacking only enzyme C) to generate a diploid strain. Sporulation (i.e. meiosis) is subsequently induced in the resulting diploid strain. What proportion of the spores (haploids formed by sporulation) is expected to grow on medium without arginine but supplemented with Compound Y? O 100% 50% 0% 25%arrow_forwardAn undergraduate researcher in your lab is studying mutations affecting the wings of Drosophila melanogaster. She has identified two mutant phenotypes of interest: bent wings (be), which are recessive to the wild-type straight wings (be+), and apterous (ap) mutants (which are wingless). The apallele is recessive to the wild-type allele (ap+), which allows wings to develop. If a homozygous bent-winged fly (which possesses the normal allele of apterous) is crossed with a homozygous wingless fly (which possesses the normal allele of bent wings), what phenotypic ratio would you expect to observe in the F2 generation of this cross? a) Please indicate the ratio, including the genotypes and phenotypes of all phenotypic classes. Phenotype: Genotype(s) corresponding to this phenotype Phenotypic ratio: (Be sure to NAME the classes in the ratio). B) Please NAME and DEFINE the type of gene interaction illustrated in this example.arrow_forwardIn the nematode C. elegans, homozygosity for the e mutant allele causes an extreme "uncoordinated" phenotype, where the worm completely loses its ability to move. Examination of 100 individuals with genotype e/e reveals that 60 mutant worm can't move at all, 35 show a very reduced ability to move, and the remaining 5 seem to have a completely wild-type phenotype with respect to movement ability. These observations suggest that e has O incomplete penetrance and variable expressivity O low expressivity and variable penetrance Ohigh expressivity and variable penetrance O high penetrance and incomplete expressivityarrow_forward
- If you wanted to produce a fly larvae with two head ends, which of the following would you do? Group of answer choices A) Add functional bicoid protein to the head end of a wildtype larva B) Add functional bicoid protein to the tail end of a mutant larva C)Add functional bicoid protein to the tail end of a wildtype larva D)Add bicoid protein from a mutant fly to the tail end of a wildtype larvaarrow_forwardYou cross two yeast strains one is an ade auxotroph the other is a pro auxotroph and allow the diploid to sporulate. When you score each spore in the ascus you find the following proportions: 518 PD, 8 NPD, and 225 T. a.) What are the genotypes of each spore in all three types of the tetrads. b) Are these genes linked why or why not? c.) If these genes are unlinked what would you expect the progeny numbers and ratios to be? d.) What is the formula to determine the most accurate distance between these genes? If linked what is the map distance?arrow_forwardConsider a Droscophilia fly with a genotype of Nn XqYY. The dominant allele of the sex-linked gene specifies a black body and the recessive a white body. The recessive autosomal allele specifies hairy bristles while the dominant allele specifies smooth bristles. i)What is the ploidy of this fly? ii) What would the sex of this fly be? iii)What would the phenotype of this fly be with respect to these two loci?arrow_forward
- In c. elegans, genetics model organism, movement problems (unc) and small body size (sma) are encoded by two mutant alleles that are recessive to those that produce wild-type traits (unc+ and sma+). A worm homozygous for movement problems and small body is crossed with a worm homozygous for the wild-type traits. The F1 have normal movement and normal body size. The F1 are then crossed with worms that have movement problems and small body size in a testcross. The progeny of this testcross is: Normal movement, normal body size 210 Movement problems, normal body size 9 Normal movement, small body size 11 Movement problems, small body size 193 a)From the test cross results, can you tell if the two genes are on the same chromosome or not? Explain your reasoning. b)What phenotypic proportions would be expected if the genes for round eyes and white body were located on different chromosomes? (please explain hot to get to these conclusions)arrow_forwardThe gene known to be mutated in cases of Agammaglobulinemia 2 (which is inherited in an autosomal recessive pattern) is the immunoglobulin lambda like polypeptide 1 (IGLL1 ENSG00000128322). What is known about the gene is recorded here: http://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000128322;r=22:23573125-23580302 Please navigate to the link above to answer the following question: Using the left-hand menu to view the sequence for IGLL1, what are the last 12 nucleic acid bases of exon 1?arrow_forwardThe gene known to be mutated in cases of Agammaglobulinemia 2 (which is inherited in an autosomal recessive pattern) is the immunoglobulin lambda like polypeptide 1 (IGLL1 ENSG00000128322). What is known about the gene is recorded here: http://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000128322;r=22:23573125-23580302 Please navigate to the link above and click, 'show transcript table', to answer the following question: What is the size in amino acid residues of the IGLL1 transcript named IGLL1-203? NOTE: Please give your answer as a number, not a word, and do not type the units.arrow_forward
- The gene known to be mutated in cases of Agammaglobulinemia 2 (which is inherited in an autosomal recessive pattern) is the immunoglobulin lambda like polypeptide 1 (IGLL1 ENSG00000128322). What is known about the gene is recorded here: http://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000128322;r=22:23573125-23580302 Please navigate to the link above and click 'show transcript table' to answer the following question: What is the NCBI accession number (including the version) of the RefSeq Match for the transcript IGLL1-202? ANSWER: The NCBI accession number (including the version) of the RefSeq Match for the transcript IGLL1-202 is "Blank 1".arrow_forwardThe gene known to be mutated in cases of Agammaglobulinemia 2 (which is inherited in an autosomal recessive pattern) is the immunoglobulin lambda like polypeptide 1 (IGLL1 ENSG00000128322). What is known about the gene is recorded here: http://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000128322;r=22:23573125-23580302 Please navigate to the link above to answer the following question: According to the web site above, how many phenotypes is IGLL1 associated with? ANSWER: IGLL1 is associated with Blank ... phenotypes.arrow_forwardThe gene known to be mutated in cases of Agammaglobulinemia 2 (which is inherited in an autosomal recessive pattern) is the immunoglobulin lambda like polypeptide 1 (IGLL1 ENSG00000128322). What is known about the gene is recorded here: http://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000128322;r=22:23573125-23580302 Please navigate to the link above and click, 'show transcript table', to answer the following question: What is the size in base pairs of the IGLL1 transcript named IGLL-202?arrow_forward
- Human Anatomy & Physiology (11th Edition)BiologyISBN:9780134580999Author:Elaine N. Marieb, Katja N. HoehnPublisher:PEARSONBiology 2eBiologyISBN:9781947172517Author:Matthew Douglas, Jung Choi, Mary Ann ClarkPublisher:OpenStaxAnatomy & PhysiologyBiologyISBN:9781259398629Author:McKinley, Michael P., O'loughlin, Valerie Dean, Bidle, Theresa StouterPublisher:Mcgraw Hill Education,
- Molecular Biology of the Cell (Sixth Edition)BiologyISBN:9780815344322Author:Bruce Alberts, Alexander D. Johnson, Julian Lewis, David Morgan, Martin Raff, Keith Roberts, Peter WalterPublisher:W. W. Norton & CompanyLaboratory Manual For Human Anatomy & PhysiologyBiologyISBN:9781260159363Author:Martin, Terry R., Prentice-craver, CynthiaPublisher:McGraw-Hill Publishing Co.Inquiry Into Life (16th Edition)BiologyISBN:9781260231700Author:Sylvia S. Mader, Michael WindelspechtPublisher:McGraw Hill Education