U5C3// BIO

Pedigree

A chart that is used to trace the phenotypes and genotypes in a family to determine whether people carry diseases or traits.

Mutation

Any change in DNA (the order of nucleotide bases/letters). It can occur in any cell in the body. Two of the types are somatic mutations and germ line mutations.

Duplication

Changes the size of chromosomes which results in multiple copies of a single gene.

Mutagen

Chemicals that can cause DNA mutations (Ex: Radiation)

Nondisjunction

Chromosomes that do not separate correctly during anaphase, resulting in 1 or 3 chromosomes rather than 2 per cell.

Explain the difference between gene and chromosomal mutations. Include an example for how each can be caused.

Gene mutations happen during DNA replication and cause a change to the original DNA sequence (Ex. Cystic Fibrosis, Dwarfism, and Sickle Cell Anemia which are often caused by replication errors or environmental mutagens). Chromosome mutations: often happen during meiosis, changing the number or location of genes (Ex. Down Syndrome, Klinefelter's Syndrome, Turner's Syndrome which are caused by duplication, translocation, and nondisjunction).

Translocation

Pieces of non-homologous chromosomes exchange segments (during crossing over).

Differentiate between point mutations and frameshift mutations.

Point mutations substitute one nucleotide for another and frameshift mutations insert or delete a nucleotide which affects all the codons that come after.

Explain the difference between a mutation in a somatic cell vs. a mutation in a gamete.

Somatic mutations occur in somatic (body) cells and are passed on by mitosis, while mutations in a gamete (Germline mutations) occur in germ line cells that give rise to gametes and are passed on by meiosis.