Mutations Mutations What are mutations, I wonder? Each baby has ~130 new mutations. Most are neutral
Mutations Mutations =Abrupt changes in the genetic material =Abrupt changes in the genetic material occurring typically during cell division. occurring typically during cell division. I think I get it. But ask me a question to check.
SOMATIC MUTATIONS SOMATIC MUTATIONS Why are these irrelevant to evolution?
Types of Mutation Types of Mutation 1. Structural changes in Chromosomes a. Loss or duplication of whole genes deletions duplications b. Changes in gene arrangement
a.Loss or duplication of whole chunks of DNA e.g. Matthew State of Univ. of California, San Francisco, has discovered variations in chromosome 7. An extra copy of a particular segment (~ 25 genes) greatly increases the risk of autism, which is leads to social isolation. But if this section is lost, it results in Williams syndrome, which leads to intense sociability .
(1) Translocation —large pieces of chromosome moved to another place in the genome. (2) Transposons —”jumping genes”—small pieces of DNA shifting within the genome. (3) Inversions —Chunks of chromosome flipping over. 2. Numerical changes in chromosomes a. Aneuploidy = addition of one or more chromosomes e.g. Extra sex chromosomes (xxy, xxyy, xxxy, etc.) b. Changes in gene arrangement
Down Syndrome Down Syndrome Extra chromosome # 21
Sperm parent cells divide every 15 days. This continuous division and copying of DNA leads to errors & the rate of error increases significantly with age. A 20 year old man will have an average of 25 new point mutations in his sperm. A 40 year old man will have 65. A 40 year old woman will have 15 But its not all due to Mom
b. Polyploidy = multiple copies of the entire genome Characteristic of several plant species e.g. Banana can be 2n = 22; 4n = 44 5n = 55
3. Gene (point) mutations = Nucleotide changes a. SUBSTITIONS DNA CAT TTA GGA GGA AAA DNA CAT TT G GGA GGA G AA