Top Posters
Since Sunday
19
19
18
15
15
14
14
13
13
13
13
12
New Topic  
wrote...
Posts: 9
Rep: 0 0
A month ago
Faulty 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 an autosomal gene. One copy of the mutated allele (A) will cause the disorder. Thus the expression of AI disorder is inherited in an autosomal dominant pattern.

In individuals that have the autosomal dominant allele the severity of the disorder is determined by mutations in a gene carried on the X chromosome. The non-severe abnormality (XN) is dominant over the 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. (1 mark)
Complete the Punnett square for the parental cross, and identify the possible phenotype ratios of the children. (2 marks)
Read 115 times
1 Reply
Replies
Answer accepted by topic starter
wrote...
Educator
Top Poster
Posts: 24771
A month ago
Sign in or Sign up in seconds to unlock everything.
First a review:

Autosomal dominant means you only need one bad dominant allele to show the effects. So, either RR or Rr will give you the traint.

Autosomal recessive means you need two copies of the bad gene to display the trait.

X-linked dominant mean that one bad copy of a gene on the X chromosome is enough to cause the genetic condition. It can affect both girls and boys.

X-linked recessive means that if there is one good copy of the gene, a person will not have the condition.

That being said, please review my answer provided in the attachment. If you're happy with it, mark it as best answer. Slight Smile
This verified answer contains over 160 words and 1 attached file(s).
Attached file
Thumbnail(s):
You must login or register to gain access to this attachment.
1
The best way to say thank you is with a positive review:

  https://trustpilot.com/review/biology-forums.com 

Your support goes a long way!


Make a note request here
Related Topics
New Topic      
Explore
Post your homework questions and get free online help from our incredible volunteers.
Learn More
Improve Grades
Help Others
Save Time
Accessible 24/7
  117 People Browsing
Your Opinion
Related Images
 968
 5532