13 Jan Week 3 Assignment

Week 3 Assignment
1. What is a linkage group? If a diploid organism contains 20 linkage groups, how many
chromosomes does the organism have in a cell? 2. Chromosomal aberrations are frequently caused by pieces of chromosomes breaking off from
the main chromosomal body, which can lead to harmful effects. Fill in the following table. (The
first one is completed for you as an example)
Type
Deletion Definition
A chromosome aberration in which a piece
of a chromosome is absent. Examples or conditions seen in human
Cri-du-chat syndrome (part of
chromosome 5 is deleted.) 3. Aneuploidy is a condition in which a person has either more or fewer chromosomes than the 46
that are normally found in humans. Down syndrome can be the result of aneuploidy.
Aneuploidy can also cause cancers. For example, lymphocytic leukemia is the result of cells
containing 3 sets of chromosome 12. What is the fundamental difference between an
aneuploidy that might lead to cancer and one that results in Down syndrome? 4. A man with Klinefelter syndrome (47, XXY) is red-green color blind, which is an X-linked recessive
disorder. His brother is normal with a 46, XY karyotype is also color blind. Both of their parents
are not color blind. Assuming that no crossing over occurred in prophase I of meiosis, explain
which parent and which X chromosome gave rise to the color-blind man with klinfelter
syndrome, as well as where the nondisjunction occurred. 5. Suppose one organism contains 2n=12 chromosomes. How many chromosomes would be
present in a cell with the following chromosome mutations?
a. Nullisomy
b. Monosomy