genetic methods Flashcards
Hereditary
Passing of physical and mental characteristics form one generation to the next
Genotype
Underlying genetic makeup of a biological organism
Phenotype
Observable characteristics of biological organism defined as physical ones or behavioural ones
Dominant allele
Shown in phenotype despite only one copy being present
Recessive allele
Only shown when two copies are present in genotype
DNA
Self replicating material found in nearly all biological organisms, carries genetic info that is needed to form proteins
RNA
Messenger that carries info from DNA
Translation
Turning genetic info found in DNA into proteins
Chromatid
Long strands of DNA found in nucleus of active cells
Coil during mitosis to form a chromosome
Chromsome
Long DNA molecule with genetic info for an organism
Gene
Single strand of DNA
Genome
Collection of genes
Locus
Genetic address of specific genes
Allele
Different version of a gene, either dominant or recessive
Pleiotropic
Traits coded by single gene within genome
Polygenic
Complex traits coded by multiple genes within genome
Who was Gregor Mendel?
-First geneticist
-Bread and cross bread peas
-Peas get one version of a trait from each parent
What are the 2 fundamental laws of Mendelian inheritance?
-Segregation - traits are either dominant or recessive
-Independence - varieties of each trait sorted independently of each other
What occurs during translation?
-Strands are unzipped and read by RNA to create proteins
What are the 4 nucleotides?
-Adenine
-Thymine
-Guanine
-Cytosine
How many chromosomes for humans have?
-46 chromsomes
-23 pairs
-Females = XX
-Males = XY
How many genes does a human have?
-Around 20,000 to 25,000
What are X linked conditions?
-Recessive traits in males are more expressed than females as they don’t have a dominant allele in their Y chromosome
Describe colour blindness
-First reported case of human X linkage
-Tends to affect males more
Describe Turner Syndrome
-X is partially missing and so affects females
-1/2,500
Describe Klinefelter Syndrome
-XXY and so affects males
-1/6000
Describe fragile X syndrome
-Repeat of gene for FMR1 protein
-Affects males and females
Describe Triple X syndrome
-3 X chromosomes
-Affects females
Describe Jacobs syndrome
-XYY
-Affects males
What is a sporadic mutation?
-Causes by error in cell division
-Can happen naturally or be due to environmental factors such as radiation
-Error in chromosomal numbers
Describe Downs syndrome
-Tends to be due to trisomy of chromosome 21
-1/1000
Describe Williams syndrome
-Due to microdeletion of chromosome 7
-1/18,000
What are polygenic traits?
-Coding from multiple genes
-Sz = affects 20 million worldwide and typically genetically predisposed
Describe the use of twin studies
-Comparing monozygotic twins and dizygotic twins
-Mz = identical
-Dz = non identical
Describe the use of genomic studies
-Look into families
-Huntingtons disease e.g. loss of motor control
-Allows to identify genetic markers
What are targeted mutations?
-Lab produced genes that are inserted into chromosome can be 2 types
-Defective = fail to produce functional protein
-Produce new and different proteins
What is genetic engineering?
-Verge of genetic revolution
-Technology that may allow us to directly edit our genome
