
Concept explainers
CASE STUDY | Art inspires learning
A genetics student visiting a museum saw a painting by Goya showing a woman with a newborn baby in her lap that had very short arms and legs along with some facial abnormalities. Wondering whether this condition might be a genetic disorder, the student went online, learning that the baby might have Roberts syndrome (RBS), a rare autosomal recessive trait. She read that cells in RBS have mitotic errors, including the premature separation of centromeres and other heterochromatic regions of homologs in metaphase instead of anaphase. As a result, metaphase chromosomes have a rigid or “railroad track” appearance. RBS has been shown to be caused by mutant alleles of the ESCO2 gene, which functions during cell division.
The student wrote a list of questions to investigate in an attempt to better understand this condition. How would you answer these questions?
What do centromeres and other heterochromatic regions have in common that might cause this appearance?

Case summary:
On visiting the museum, the genetics student noticed a painting made by the Goya. In the painting, a woman was drawn with the baby in her lap, the baby had very little arms and legs along with some facial abnormalities. The student wonders about the condition, that it might be a genetic disorder. Through the online research, he reached to the conclusion that the baby might have RBS (Roberts syndrome), it is a rare autosomal recessive trait. In this disorder, the cells suffered from the mitotic errors that include the early separation of the centromeres and also heterochromatic regions of the homologous chromosomes at the stage of the metaphase instead of anaphase. RBS is caused by the mutated alleles of the ESCO2 gene, that has a role in the cell division.
Characters in the case:
A genetics student and a painting of a baby withvery little arms and legs along with some facial abnormalities.
Adequate information:
Facts of the case that brings in major impact are the limbs and facial abnormality in the painting of a baby, which a genetic student interpreted as RBS (Roberts syndrome) that iscaused by the mutated alleles of the ESCO2 gene.
To determine:
The common thing in between the centromere and other heterochromatic regions that causes the abnormal appearance in the RBS.
Given information:
The newborn baby had many facial abnormalities and also the length of the arms and legs are comparatively short.
Explanation of Solution
Roberts syndrome is the extremely rare genetic disorder that is due to the disrupted cell division that leads to the malformation of the bones, face, arms, legs and the skull. On chromosome number 8, a mutation in the gene ESCO2 results in the Roberts syndrome.
In a normal individual, during the cell division the copied chromosomes attach themselves to the centromeres but in RBS the newly formed chromosomes are not frequently attached themselves with the centromeres. Due to which the proper alignment of the chromosomes does not takes place.
PCS (premature chromosomal separation) occurs in the RBS as the chromosomes that are supposed to separate at the anaphase stage separates at the metaphase stage. Another chromosomal abnormality is that HR (heterochromatin repulsion), chromosomes that are having the HR experiences the heterochromatin separation at the metaphase stage. Both of these chromosomal abnormalities displays a railroad track appearance as they both lack the primary constriction and also the heterochromatin repulsion.
Therefore, it can be concluded that centromeres and the other heterochromatin regions both are separated at the metaphase stage that could cause the abnormality in the baby having RBS.
Want to see more full solutions like this?
Chapter 11 Solutions
Essentials of Genetics (9th Edition) - Standalone book
- How many milligrams of zinc did you consume on average per day over the 3 days? (See the Actual Intakes vs. Recommended Intakes Report with all days checked.) Enter the number of milligrams of zinc rounded to the first decimal place in the box below. ______ mg ?arrow_forwardthe direct output from molecular replacement is a coordinate file showing the orientation of the unknown target protein in the unit cell. true or false?arrow_forwardthe direct output from molecular replacement is a coordinate file showing the orientation of the unknown target protein in the unit cell. true or false?arrow_forward
- Did your intake of vitamin C meet or come very close to the recommended amount? yes noarrow_forwardWhich of the following statements about hydration is true? Absence of thirst is a reliable indication that an individual is adequately hydrated. All of these statements are true. Although a popular way to monitor hydration status, weighing yourself before and after intensive physical activity is not a reliable method to monitor hydration. Urine that is the color of apple juice indicates dehydration. I don't know yetarrow_forwardThree of the many recessive mutations in Drosophila melanogaster that affect body color, wing shape, or bristle morphology are black (b) body versus grey in wild type, dumpy (dp), obliquely truncated wings versus long wings in the male, and hooked (hk) bristles versus not hooked in the wild type. From a cross of a dumpy female with a black and hooked male, all of the F1 were wild type for all three of the characters. The testcross of an F1 female with a dumpy, black, hooked male gave the following results: Trait Number of individuals Wild type 169 Black 19 Black, hooked 301 Dumpy, hooked 21 Hooked, dumpy, black 172 Dumpy, black 6 Dumpy 305 Hooked 8 Determine the order of the genes and the mapping distance between genes. Determine the coefficient of confidence for the portion of the chromosome involved in the cross. How much interference takes place in the cross?arrow_forward
- What happens to a microbes membrane at colder temperature?arrow_forwardGenes at loci f, m, and w are linked, but their order is unknown. The F1 heterozygotes from a cross of FFMMWW x ffmmww are test crossed. The most frequent phenotypes in the test cross progeny will be FMW and fmw regardless of what the gene order turns out to be. What classes of testcross progeny (phenotypes) would be least frequent if locus m is in the middle? What classes would be least frequent if locus f is in the middle? What classes would be least frequent if locus w is in the middle?arrow_forward1. In the following illustration of a phospholipid... (Chemistry Primer and Video 2-2, 2-3 and 2-5) a. Label which chains contain saturated fatty acids and non-saturated fatty acids. b. Label all the areas where the following bonds could form with other molecules which are not shown. i. Hydrogen bonds ii. Ionic Bonds iii. Hydrophobic Interactions 12-6 HICIH HICIH HICHH HICHH HICIH OHHHHHHHHHHHHHHHHH C-C-C-C-C-c-c-c-c-c-c-c-c-c-c-c-C-C-H HH H H H H H H H H H H H H H H H H H HO H-C-O H-C-O- O O-P-O-C-H H T HICIH HICIH HICIH HICIH HHHHHHH HICIH HICIH HICIH 0=C HIC -C-C-C-C-C-C-C-C-CC-C-C-C-C-C-C-C-C-H HHHHHHHHH IIIIIIII HHHHHHHH (e-osbiv)arrow_forward
- Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage LearningBiology: The Dynamic Science (MindTap Course List)BiologyISBN:9781305389892Author:Peter J. Russell, Paul E. Hertz, Beverly McMillanPublisher:Cengage LearningBiology: The Unity and Diversity of Life (MindTap...BiologyISBN:9781305073951Author:Cecie Starr, Ralph Taggart, Christine Evers, Lisa StarrPublisher:Cengage Learning
- Biology 2eBiologyISBN:9781947172517Author:Matthew Douglas, Jung Choi, Mary Ann ClarkPublisher:OpenStaxBiology: The Unity and Diversity of Life (MindTap...BiologyISBN:9781337408332Author:Cecie Starr, Ralph Taggart, Christine Evers, Lisa StarrPublisher:Cengage LearningBiology (MindTap Course List)BiologyISBN:9781337392938Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. BergPublisher:Cengage Learning





