Concept explainers
A person is simultaneously heterozygous for two autosomal genetic traits. One is a recessive condition for albinism (alleles A and a); this albinism gene is found near the centromere on the long arm of an acrocentric autosome. The other trait is the dominantly inherited Huntington disease (alleles HD and HD+). The Huntington gene is located near the telomere of one of the arms of a metacentric autosome. Draw all copies of the two relevant chromosomes in this person as they would appear during metaphase of (a) mitosis, (b) meiosis I, and (c) meiosis II. In each figure, label the location on every chromatid of the alleles for these two genes, assuming that no recombination takes place.
Want to see the full answer?
Check out a sample textbook solutionChapter 4 Solutions
ND STONY BROOK UNIVERSITY LOOSELEAF GENETICS: FROM GENES TO GENOMES
- Amelogenesis imperfecta (AI) is a disorder of faulty tooth enamel formation. It is inherited in an autosomal dominant and X-linked dominant pattern. The expression of AI disorder is determined by mutations in the autosomal alleles. One copy of the mutated allele (A) will cause the disorder. The severity of the disorder is determined by mutations in a gene carried on the X chromosome. Normal (or non-severe) abnormality (XN) is dominant over the abnormality (or severe) (Xn) allele. In the absence of the autosomal dominant allele, the abnormality gene on the X chromosome is not expressed. Question:A woman with normal teeth had four children with a man with non-severe form of AI: A boy was born without amelogenesis imperfecta A girl was born without amelogenesis imperfecta A boy was born with severe amelogenesis imperfecta A boy was born with non severe amelogenesis imperfecta Identify the parental genotypes. Complete the Punnett square for the parental cross, and identify the…arrow_forwardAn animal is heterozygous for two autosomal genetic traits found on different chromosomes. Purple fur is inherited dominantly (with pp genotype giving green fur) and the gene is located near the telomere on the short arm of an acrocentric autosome. The gene for claw sharpness is located closer to the centromere on one arm of a metacentric chromosome. The S+ allele is dominant and results in sharp pointy claws, while the SS genotype gives the animal rounded dull claws. Create and label a diagram showing all possible arrangements of the chromosomes involved in these traits’ inheritance during metaphase 1.arrow_forwardTay Sachs is a rare autosomal recessive disorder that causes mental and physical disabilities leading to death in infants. Affected individuals are lacking the enzyme hexosaminidase, causing lipids to build up in the brain.The HEXA gene on chromosome 15 codes for hexosaminidase, and a four base pair insertion in the gene results in an altered reading frame and non-functional enzyme being produced. Individuals who are carriers (heterozygotes) of the Tay-Sachs allele are not affected by the disease but appear to have increased protection against tuberculosis.The incidence of Tay-Sachs disease is much higher among Ashkenazi Jews originating from Eastern Europe than the general population of the United States. About 1 in 3 500 babies of Ashkenazi Jewish heritage are born with Tay-Sachs disease and about 1 in 30 Ashkenazi Jews are carriers compared to about 1 in 320 000 babies born with the disease and about 1 in 300 carriers in the general United States population. Ashkenazi Jews living in…arrow_forward
- In humans, hemophilia is an X-linked recessive disorder that affects the gene for factor VIII protein, which is essential for blood clotting. The dominant and recessive alleles for the factor VIII gene are represented by H and h. Albinism is an autosomal recessive condition involving the tyrosinase enzyme which synthesizes pigment. Alleles of tyrosinase are represented by A and a. The provided pedigree shows a new marriage between Clara and Charles. A) Review the pedigree, filling in any genotypes that can be determined from the displayed traits. B) What is the probability that their first child will display hemophilia, albinism, or BOTH hemophilia AND albinism.C) If Clara and Charles first child has albinism, what is the probability that the second child will also display albinism?arrow_forwardPompe disease is a glycogen storage disorder caused by a lack of a-glucosidase, the enzyme that converts glycogen to glucose in the muscles. Babies born with this disorder die by the age of two. Pompe disease is a genetic disorder caused by the presence of two recessive autosomal alleles. A man and a woman heterozygous for the condition have two female unaffected children. Determine the probability, expressed as a whole number percentage, of a third baby being born a male with Pompe disease. Your answer must include the use of a Punnett square as well as a legend indicating the allele symbols used.arrow_forwardTuberous Sclerosis (TS) is an autosomal dominant genetic disease characterized by seizures, mental retardation, autism, and benign tumors of the brain, heart, skin, and kidneys. The kidney tumors can also be malignant. This disease exhibits a wide range of severity, and only about 1/3 of the cases are inherited. Two different genes have been tightly linked to the disease in families where it is inherited. The remaining 2/3 appear to be due to mutations in one of the 2 genes as well. Overall it appears that 1/2 are caused by mutations in TSC1 and the other half by mutations in TSC2. A rat model for hereditary renal carcinoma (kidney cancer) has been found. Southern and Northern blot analysis of the TSC1 and TSC2 gene revealed no differences between these rats and normal rats. Not all the rats in the strain would get cancer but a significant proportion did and those were selected for and used in experiments. 1. a) What was detected by the Southern blots? (look this up, make your…arrow_forward
- Regarding Mendelian inheritance in diploid individuals, (Read each statement carefully. Select all of the statements below that are true (that you agree with). Leave any statements that are false (that you do not agree with) un- selected.) a diploid individual receives two copies of every autosome from the previous generation. for every autosomal gene inherited by an individual, both copies can come from one parent. a diploid individual gives two copies of every autosome to a child in the next generation. to be diploid means that two independent genes are specified in the individual's genotype.arrow_forwardFaulty Tooth Enamel Formation Amelogenesis imperfecta (AI) is a disorder of faulty tooth enamel formation. It is inherited in an autosomal dominant and X-linked dominant pattern. The expression of AI disorder is determined by mutations in the autosomal alleles. One copy of the mutated allele (A) will cause the disorder. The severity of the disorder is determined by mutations in a gene carried on the X chromosome. Normal (or non-severe) abnormality (XN) is dominant over the abnormality (or severe) (Xn) allele. In the absence of the autosomal dominant allele, the abnormality gene on the X chromosome is notexpressed. Question:A woman with normal teeth had four children with a man with non-severe form of AI: A boy was born without amelogenesis imperfecta A girl was born without amelogenesis imperfecta A boy was born with severe amelogenesis imperfecta A boy was born with non severe amelogenesis imperfecta Identify the parental genotypes. Complete the Punnett square for the parental…arrow_forwardThe following Pedigree shows an unknown genetic disorder. The disorder is believed to be caused by single gene mutations. For the following disorder, determine whether the mutant gene is located on an autosome or X chromosome. arrow_forward
- Neurofibromatosis-1 (NF1) is an autosomal dominant disorder where tumours form in the base layer of the skin or in nerve tissues. What is the probability that individuals II-1 and II-2 will have a genetic son with NF1? Find the image attached.arrow_forwardAlbinism, lack of pigmentation in humans, results from an autosomal recessive gene designated a. Two parents with normal pigmentation have an albino child. What is the probability that their next child will be albino? What is the probability that the next child will be an albino girl? If the child is normal, what is the probability that it will be a carrier (heterozygous) for the albino gene?arrow_forwardMaple syrup urine disease (MSUD) is an autosomal recessive metabolic disorder that presents in newborns, typically within the first 48 hours after birth. As the name suggests, a key indicator of the disease is the presence of a sweet odor in the urine that smells like maple syrup. Left untreated, MSUD can result in failure of central neurological function and the respiratory system and can be fatal. MSUD is caused by mutations in components of the branched-chain alpha-keto acid dehydrogenase complex (BCKDC). These mutations result in the inability for cells to break down branched-chain amino acids (BCAAs). BCAAs and their byproducts accumulate and are excreted in the urine, giving rise to the maple syrup scent. QUESTIONS: Draw the structures of the three branched-chain amino acids (BCAA). Draw the structures of the three BCAA products released by functional BCKDC. Indicate the original amino acid.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