Thursday, November 17, 2011

Scribe Post: Wednesday November 16 and Thursday November 17

Hey guys, sorry I didn't see this until today!!

Yesterday in class we went over the homework pages and learned how to analyze a pedigree chart. Here's what you need to know:

Basic Key/General Ideas:
Squares represent males and circles represent females.
If it's unshaded it has a dominant trait, either TT or Tt. If its shaded it's recessive; tt.
If its half shaded and half unshaded, it represents a sex-linked chromosome.

Each of the lines represents something:
The horizontal lines between two are called "marriage lines". They show the marriages or parents or in-laws.
The vertical lines are "children lines".
You read the sibling lines from left to right in order of oldest to youngest.

ALSO it's a smart idea to label the rows. :)
The row is called the P1 Generation.
The next is the F1 Generation.
The next is the F2 Generation.

To solve this, start by marking everything that is shaded with two recessive genes (tt). Then go back and give everything blank ONE dominant gene. Then go back and try to solve as many as you can based on the clues.
Sometimes they can't be solved!!!

Today in class we had a shortened schedule because of Late Arrival. We took notes on the Chromosomal Theory of Inheritance and worked on homework.

Terms to know:
  • Gene linkage- alleles that start out on the same chromosome and travel together during meiosis and fertilization. Ex: Red hair and freckles.
  • Y Chromosome- 1/3 the size of X chromosome, male chromosome.
  • Genes are located on chromosomes and the behavior during meiosis results in the inheritance patterns
  • Gene linked alleles do NOT follow Mendel's principle of independent assortment.
  • Y chromosomes are believed to have evolved from autosomes
  • Passes from father to to son, can trace ancestry lines!

Your homework:
1. UP p. 73-77 & 81-88 due Monday
2. EC - UP p. 79-80 Due Friday
3. QUIZ Friday
4. TEST Tuesday
5. trihybrid due Monday



  1. Hey Anna,
    You did a great job with this! Your images really help clarify what you wrote.
    However, you have a typo. In the highlighted words under basic key/general ideas, you wrote that when a circle or square is unshaded, then it is recessive. Although I'm sure you meant to write if a shape is shaded, then it is recessive.
    Also, just to clarify, when a circle or square is half shaded, it indicates that a recessive allele is masked by a dominant allele in sex-linked traits. You should also be sure to add that this is only possible in females because they can have two different alleles on both of their X sex chromosomes. This is not possible in males because they have only one X sex chromosome and therefore will only have one allele.
    Otherwise great job! Hope everyone did well on the quiz today!

  2. Hey Anna Busch,
    I think that your post was really effective in explaining pedigrees. You made effective use of the charts and pictures, but as Sophia said, you did have a minor spelling mistake. That kind of is a key mistake... Overall though, you were effectivein describing the class and explaining a complex topic.

  3. Hey Anna!,
    This was very organized and informative!
    In my opinion, I think the second image was a lot more clearer and could be better understand than the first one.
    Good job, Anna!

  4. Thanks Sophia! I fixed it. :)

  5. Nice job Anna!! You had to do two days of posts so you get points for that ;) Anyway apparently you fixed the typo so good job on that. Also I like how you used two pictures because one of them demonstrates half vs. full shading and the other shows the different generations and how those are labeled (I, II, III...) So ya I really liked your post because it covered everything while being very concise! :)

  6. Thanks Anna for the background knowledge on the scientists along with the pictures! I'm a visual learner so I think this helped a lot.