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What does a homozygous gene look like?
- Two capital letters or two lower case letters.
- Ex: GG or gg
What does a heterozygous gene pair look like?
- One capital letter and one lower case letter.
- Ex: Jj
What does a dominant gene pair look like?
- One capital letter and one lower case letter or two capital letters.
- Ex: Uu or UU
What does a recessive gene pair look like?
- Two lower case letters.
- Ex: pp
What is a gene mutation?
Any chemical change that affects the DNA molecule
What is a chromosomal mutation?
A change that occurs in the number or structure of a chromosome
What is inversion?
- A chromosomal mutation where a part of a chromosome becomes oriented in the reverse of its usual direction (mostly harmless)
What is duplication?
- A chromosomal mutation where a segment of chromosome is repeated
What is deletion?
- A chromosomal mutation where part of the chromosome is lost
What is translocation?
- A chromosomal mutation where part of a chromosome breaks off and attaches to another nonhomologous chromosome
What is nondisjuction, and what is one example in humans?
- A chromosomal mutation where there is a failure of homologous chromosomes to separate normally during meiosis
- An example is Down Syndrome where there is a nondisjunction of chromosome 21, causing the embryo to have 3 21's instead of 2
What is a polyploidy, and what is an example in humans?
- A chromosomal mutation where an organism has extra sets of chromosomes
- An example is Klinefelter's Syndrome where there is an extra set of sex chromosomes and the embryo is XXY