2009 Insight Into Blindness

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2009: Insight Into Blindness: Whanau-Science Partnership for Discovery

José Manuel deserted from a whaling ship in the 1830’s and went to live with a Māori tribal community in the East Cape of Aotearoa‐New Zealand. He took multiple wives (as was normal for this community) and now over a 180 years later has more than 10,000 descendents. In one branch of this whanau, more than 40 of the family who are alive today are either blind or have extremely poor vision. Their vision may be so bad that they can hardly distinguish between light and dark. While having a serious vision impairment makes life very challenging, for some members of the whanau there is an additional inherited challenge. As well as their vision problems, a number of the boys in more recent generations are affected by intellectual disabilities and autism.

Dr Marion Maw, a geneticist from the Department of Biochemistry at the University of Otago studying molecular genetics of inherited disorders of the retina was a part of the team of scientists who worked with this whanau to help discover why so many of them suffer from blindness and vision impairment.

This Insight Into Blindness Seminar includes these resources to assist your learning :

Insight into Blindness Question Page.

Insight into Blindness Discussion Page

The Seminar Paper and Questions

Answer the post-seminar challenge questions:

1. (a) Explain what a Barr Body is and why they are only found in females.
(b) How could the presence of Barr Bodies may affect the phenotype of a female who is:
Heterozygous for an x‐linked gene
Homozygous for an x‐linked gene
(c) All the females in the family who are affected are heterozygous for the mutation. Within the
females in the whanau, there is variation in the severity of the vision impairment. What
biological explanation could account for this variation in the heterozygous female phenotype ?

2. What evidence from the family tree suggests that this is an x‐linked condition?

3. Compare person 16 in generation VII (affected) with person 17 in generation VI (unaffected). What does the difference between the microsatellite pattern for these two individuals tells us about where on the chromosome the mutation is? Look at the sequence “2 2 6”.

4.Compare person 45 in generation VII (unaffected) with person 48 in generation VII (affected). The difference between these two individuals confirmed for the scientists that the mutation must be in the middle section of the chromosome where the satellite pattern “1 1 3 2” was found. What evidence did they use to come to this conclusion?

Insight into Blindness Question Page.

Insight into Blindness Discussion Page

Links to your school programme

This seminar links to NCEA Level 3 Achievement Standards:

  • AS 90715  Describe the role of DNA in relaton to Gene Expression 
  • AS 90718 Describe Applications of Biotechnological Techniques
  • AS 90714 Research a Contemporary Biological Issue

A list of objectives from your Year 13 programme that link into the seminar can be found in the Questions and Disucssion Handout.

About the Researchers and Presenters

Ariana Hemara-Wahanui   |  Patricia Lundon-Treweek  |   Marion Maw | 

Jacquie Bay   |  Peter Dearden   |   Waiora Port   |    

Useful Links and References to Online Papers

Read the scientific paper that Ariana and the team published to share thier findings with other scientists and clinicians.  Hemara-Wahanui A et al (2005) CACNA1F mutation identified in an x-linked retinal disorder shifts the voltage dependence of Cav1.4 channel activation PNAZ vol 102 no. 21 7553—7558

Gene Therapy for Leber Congenital Amaurosis

Autism New Zealand

Royal New Zealand Foundation for the Blind