Genetic Disorders Assignment

Single Gene Genetic Disorders

Your Task:  Research the following information about a single-gene genetic disorder of your choosing and write up a short summary on your Google account or on MS Word, which you will then copy and paste into a comment on this blog post.

1. Choose any one of the single-gene genetic disorders listed below and research it. You can highlight the disorder, copy it, and paste it into a Google search.
2. Learn if the disorder is sex-linked or autosomal and dominant or recessive.
3. Find out which chromosome the mutation is on, and what problems are caused by the mutated gene.
4. Describe the phenotype of people with this disorder.
5. Include references of where you got your information.
6. Submit your typed paragraphs as a comment on this post:
      a. Click on “Comments” at the end of this post
      b. Type in or paste your paragraphs about the disorder you chose to research and click “Publish”
      c. You will be required to log in to your Google account to create a blogger profile, which should be your first name and last initial (mine would be Ryan H), which identifies the comment as yours
      d. Make sure your comment appears as you want it
      e. Log out of your Google Account
      f. You're done!

Familial hypercholesterolemia             X-linked vitamin d-resistant rickets
Polycystic kidney disease                     Colorblindness
Neurofibromatosis type I                      Achondroplasia (dwarfism)
Hereditary spherocytosis                      Male patterned baldness
Marfan syndrome                                 X-linked ichthyosis
Huntington's disease                            East syndrome
Sickle cell anemia                                Gunther disesase
Cystic fibrosis                                      Diastrophic dysplasia
Tay-Sachs disease                               Apert syndrome (webbed digits)
Phenylketonuria                                   Niemann–Pick disease
Mucopolysaccharidoses                       Xeroderma pigmentosum
Lysosomal acid lipase deficiency         Vici syndrome
Glycogen storage diseases                  Oguchi disease
Galactosemia                                       Sabinas brittle hair syndrome
Duchenne muscular dystrophy            Roberts syndrome
Hemophilia

Non-Mendelian Genetics

Some characteristics aren't inherited in a simple dominant and recessive fashion, in which the heterozygote has the identical phenotype to the homozygous dominant individual. Although genetics gets even more complicated than this, we'll explore 3 trickier situations: incomplete dominance, codominance, and sex-linked traits.

Incomplete dominance: situation in some genes in which the heterozygote is an intermediate (blend) of the parent phenotypes. One example is flower color in carnations and snapdragons. cR= red and cW= white, and red and white individuals are homozygous. The heterozygotes made by crossing these 2 purebred homozygotes are all pink. See the diagram below.




Codominance: there exists more than 1 dominant allele; sometimes there's also a recessive allele. A prime example is with the ABO blood group. "A" indicated the presence of the "A" antigen (glycoprotein) on the surface of the red blood cells, "B" indicates the "B" antigen, "AB" indicates the presence of both, and "O" indicates no antigen is present. The O phenotype is caused by a homozygous recessive condition, while the other phenotypes are caused by the presence of one or two dominant alleles (A and B are both dominant). All possible combinations of alleles and phenotypes are listed below.



Sex-linked genes: Genes found on the X or Y chromosomes (not the autosomes, chromosomes 1-22) are inherited differently between the sexes. Generally speaking, women are XX and men are XY. Any disease associated with the Y chromosome will only be found in men, since women don't receive that chromosome; the X works differently. If a man inherits a recessive (non-functional) allele on his one X chromosome, he is out of luck—he can't make the necessary protein! Women are better off, since they need both X chromosome alleles they inherit to be recessive to show the recessive (diseased) phenotype. Check out the Punnett Square for the sex-linked condition of red-green colorblindness, which is much more common in men.