MUTATIONS Stumpy Video

So what happened to Stumpy?

So then what happened? What are possible causes of this?

Are all Stumpy’s cells affected? Possible scenario #1: DNA was miscopied when his parents gametes were formed = all cells in the body have this mutation Possible scenario #2: When he was developing, DNA was miscopied in the stem cells (unspecialized cells) that became legs = only those cells have the mutation Answer = We don’t know! How could we find out?

Types of DNA mutations: Single gene mutations Only affects a single gene Also called point mutations Chromosomal mutations Affects multiple genes at a time

Single Gene / Point Mutations: Example 1 – What happens? T C A G T C A T C A G C  T A G T C A T C A G C Deletion – all bases shift left/back after mutation Example 2 – What happens? T C A G T C A T C A G C  T C C A G T C A T C A G C Addition – all bases shift right/forward after the mutation Example 3 – What happens? T C A G T C A T C A G C  T A A G T C A T C A G C Substitution – only one codon affected

Chromosomal Mutations: Deletion Addition Inversion Translocation

Other DNA / Chromosomal abnormalities? Fertilized egg partially splits in utero or twins cells fuse in utero = conjoined twins Extra or missing chromosomes can result in disorders –Downs syndrome, Turners syndrome, Klinefelter's syndrome… ***We can discuss these during our genetics unit***

What are some DNA mutations in humans? Sickle Cell Anemia video Caused by only one base pair substitution Albinos Cause by a mutation in one of a few genes that are know to produce melanin Why is the albino trait more common in humans or pets than in wild animals