Human Heredity: Principles and Issues
Human Heredity: Principles and Issues
11th Edition
ISBN: 9781305683952
Author: Michael Cummings
Publisher: Cengage Learning US
bartleby

Videos

Textbook Question
Book Icon
Chapter 5, Problem 1CS

After hearing this information, should Sue and Tim feel that their chances of having a child with a cleft lip are increased over that of the general population?

Sue and Tim were referred for genetic counseling after they inquired about the risk of having a child with a cleft lip. Tim was born with a mild cleft lip that was surgically repaired. He expressed concern that his future children could be at risk for a more severe form of clefting. Sue was in her 12th week of pregnancy, and both were anxious about the pregnancy because Sue had had a difficult time conceiving. The couple stated that they would not consider terminating the pregnancy for any reason but wanted to be prepared for the possibility of having a child with a birth defect. The genetic counselor took a three-generation family history from both Sue and Tim and found that Tim was the only person to have had a cleft lip. Sue’s family history showed no cases of cleft lip. Tim and Sue had several misconceptions about clefting, and the genetic counselor spent time explaining how cleft lips occur and some of the known causes of this birth defect. The following list summarizes the counselor’s discussion with the couple.

  • Fathers, as well as mothers, can pass on genes that cause clefting.
  • Some clefts are caused by environmental factors, meaning that the condition didn’t come from the father or the mother.
  • One child in 33 is born with some sort of birth defect.
  • One in 700 is born with a cleft-related birth defect.
  • Most clefts occur in boys; however, a girl can be born with a cleft.
  • If a person (male or female) is born with a cleft, the chances of that person having a child with a cleft, given no other obvious factor, is 7 in 100.
  • Some clefts are related to identifiable syndromes. Of those, some are autosomal dominant. A person with an autosomal dominant gene has a 50% probability of passing the gene to an offspring.
  • Many clefts run in families even when there does not seem to be any identifiable syndrome present.
  • Clefting seems to be related to ethnicity, occurring most often among Asians, Latinos, and Native Americans (1 : 500); next most often among persons of European ethnicity (1 : 700); and least often among persons of African origin (1 : 1,000).
  • A cleft condition develops during the fourth to the eighth week of pregnancy. After that critical period, nothing the mother does can cause a cleft. Sometimes a cleft develops even before the mother is aware that she is pregnant.
  • Women who smoke are twice as likely to give birth to a child with a cleft.
  • Women who ingest large quantities of vitamin A or low quantities of folic acid are more likely to have children with a cleft.
  • In about 70% of cases, the fetal face is clearly visible using ultrasound. Facial disorders have been detected at the 15th gestational week of pregnancy. Ultrasound can be precise and reliable in diagnosing fetal craniofacial conditions.
Expert Solution & Answer
Check Mark
Summary Introduction

To determine: Whether the chances of Ms. S and Mr. T having a child with a cleft lip is increased over the general population.

Introduction: Ms. S was 12 weeks pregnant. Mr. T was born with a mild cleft lip which was surgically repaired, but there was no similar past family history. Ms. S’s family history had no cases of cleft lip. They were concerned if their future child would be born with a more severe form of clefting. They had several misconceptions about clefting, which were cleared to them by the genetic counselor.

Explanation of Solution

The chances of Ms. S and Mr. T having a child with a cleft lip are not much evident because of the following reasons:

  • With reference to the case study, a person with an autosomal dominant gene has a 50% probability of passing the gene to an offspring. Ms. S and Mr. T do not have any family history of cleft lip, which implies that there are no genes that can predispose their child to the cleft lip.
  • Mr. T was the only one in the family who had a cleft lip. His development of cleft lip is most likely due to the environmental factors. Moreover, there are only 7 in 100 cases of a child born with a cleft lip if one of the parents had a history of cleft lip.

Hence, it can be concluded that Ms. S and Mr. T should not be worried about their child to develop a cleft lip as the chances are quite low.

Want to see more full solutions like this?

Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!
Students have asked these similar questions
6. The mammalian phylogenies (labeled a and b) were produced by two different research groups. a. In which tree do phylogenetic relationships most closely align with biogeography and why? (consult the Teeling and Hedges paper) b. What are the most closely related species to Chiroptera in each tree? Might the use of convergent traits for building phylogenies explain this difference? If so, which tree is most likely to have relied on convergent traits and why? c. What are some possible reasons that the two research groups came up with different phylogenies (in general terms)? describe at least three possible reasons.
Build a model of a prokaryotic cell using any material of your choice. In your model be sure to include all the structures appropriate to your cell. You may model a bacterial cell or an archaea. You will model at least 4 structures in any model. Next, build a model of a virus using the same type of materials. You may choose any type of virus but be sure you can illustrate the key features of a virus (head shape for example). Once complete, take multiple photographs of your models from all angles. Include these images in a document that also contains the following completed table format. You may need to add rows to your table depending on the type of prokaryote you model. Structure Model Key Found in Different in Function Virus Virus Once your model is complete, write a brief description of your cell and your virus. Emphasize features that are absent in viruses that classify them as non-living. You can refer to specific structures in your table in this explanation. Some suggestions for…
(This is a 2-part work, Part 1 is done, only Part 2 is to be worked on at the bottom)Part 1 (Done): Describe the levels of structural hierarchy for the human body, starting with the organismal level and ending with the chemical level. In addition, you should make sure you link each level to the previous level, emphasizing the structural relationships. The human body is organized into a structural hierarchy that progresses from the macroscopic organismal level down to the microscopic chemical level. Each level builds upon the previous one, creating increasingly complex structures. Below is the hierarchy, from largest to smallest, with explanations linking each level to its predecessor:   1. Organismal Level The entire living human body.Relationship: All lower levels work together to sustain life at this highest level.   2. Organ System Level Groups of organs working together to perform major functions.Examples: circulatory, nervous, digestive systems.Relationship: The organismal…

Chapter 5 Solutions

Human Heredity: Principles and Issues

Knowledge Booster
Background pattern image
Biology
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, biology and related others by exploring similar questions and additional content below.
Similar questions
SEE MORE QUESTIONS
Recommended textbooks for you
Text book image
Human Heredity: Principles and Issues (MindTap Co...
Biology
ISBN:9781305251052
Author:Michael Cummings
Publisher:Cengage Learning
Text book image
Health Safety And Nutrition F/Young Child
Health & Nutrition
ISBN:9781305144767
Author:MAROTZ
Publisher:Cengage
Text book image
Nutrition Through The Life Cycle
Health & Nutrition
ISBN:9781337919333
Author:Brown, Judith E.
Publisher:Cengage Learning,
Text book image
Essentials Of Human Development
Biology
ISBN:9781285647357
Author:Kail
Publisher:Cengage
Text book image
Medical Terminology for Health Professions, Spira...
Health & Nutrition
ISBN:9781305634350
Author:Ann Ehrlich, Carol L. Schroeder, Laura Ehrlich, Katrina A. Schroeder
Publisher:Cengage Learning
Text book image
Comprehensive Medical Terminology
Nursing
ISBN:9781133478850
Author:Jones
Publisher:Cengage
The Human Reproductive System; Author: Professor Dave Explains;https://www.youtube.com/watch?v=TucxiIB76bo;License: Standard YouTube License, CC-BY