Today in Mrs. Stein’s biology class we learned about multiple alleles. Multiple alleles are a gene with two or more possible varieties. The most common example is the human blood types A, B, AB, and O. in theses blood types, types A and B are codominant, and type O is recessive.
A fun fact about blood types is that they are defined by what antigens are on the red blood cells.
We also talked about genetic disorders. There are three types of genetic disorders:
-Chromosome abnormalities- a mess up in the chromosomal order. A major example of this is Downs Syndrome.
-Single gene disorders-were a mutation is on only one gene
-Sex linked disorders- these are disorders in the chromosomes that determine the gender of an organism.
Here are some major facts about genetic disorders:
-they are a mutation in the DNA
-there are 22pairs of autosomes and 1 pair of sex chromosomes.
-many genetic disorders are autosomal and recessive
We then went on to talk about sex linked disorders; here are some facts about them:
-sex linked disorders are on the X chromosome only (in the sex pair there is either
XX-female or XY- male) and many are recessive.
-hemophilia, colorblindness, muscular dystrophy, and baldness are all examples of sex linked disorders.
In order of diseases to show in a woman she must have the disease on both Xs (XaXa), and only on the one x for men (YXa). So women can be carriers(XAXa), but men cannot.
We then quickly covered pedigrees before the bell rang. All pedigrees are, are what is used to trace a disease through family. And that’s when the bell rang ending class.
Here are some links to some videos if you need them:
This one explains a lot a bout how to use multiple alleles in a punnet squarehttp://www.youtube.com/watch?v=ROL5ekow-Y4
This one shows more on how a genetic disorder occurs and how it affects peoplehttp://www.youtube.com/watch?v=8s4he3wLgkM
This one shows some diferent types of genetic disordershttp://www.youtube.com/watch?v=eHQiwX5SSgM
The next scribe will be Michael D.
No comments:
Post a Comment