Irwins q's Flashcards
Gene
Segment of DNA that encodes a protein, BRCA1 gene
Allele
Different versions of the same gene, Blood type A B
Homozygous
Having 2 identical allels, AA aa
Heterozygous
Two different alleles, Aa
Dominant
An allele that reduces the ability of recessive allele, huntingtons
Recessive
AN allele that is reduced by the dominant, cystic fibrosis
Codon
Sequence of AA that specifies a protein, AUG PS
Polymorphism
Common genetic vriation, MTHFR
Haploid
Cells containing only 1 set of chromosomes, 23 egg cells
Hiploid
2 sets, somatic cells 46
Genome
DNA containing all its genetic components
Exon
Coding region of a gene expressed as a protein
Intron
Non-coding region that’s removed during mRNA processing
Autosomal dominant inheritance
Single copy of gene causes mutation,
Feature: 50% chance. passes generations, HTT causes huntingtons
Autosomal recessive inheritance
Two copies of mutated gene required to cause the inheritance
Features: Gene from each parent inherited, Parent may be asymptomatic, e.g cystic fibrosis from CTFHR
X- linked inheritance
Mutation in X - Chrom
Females are carriers but need 2
e.g DMD, duchene muscular dystrophy
X-linked dominant
Single mutation on the x allele
Fragile X syndrome FMR1 mutation
Pre implantation genetic diagnosis
Person with disorder can have kids without having it
egg fertilised 3-5 days embryo divides
Cell removed and DNA analysed, determines which don’t have mutation
Then transferred to uterus
Pre natal testing
Performed when risk of chromosomal abnormality
2 types invasive and non invasive
Maternal serum screening
Blood test for DS, Low AFP _ high HCG = DC
New born screening
Carried out after birth
Detects for high levels of phenylalalnine
Predictive testing
Identifies mutations that inc the risk of patient developing disorder
mutation = development of disorder possible
Presymptomatic testing
Determines if a person will develop disorder before signs appear
used to check for huntingtons
