Genetics and Genomics Flashcards
Define a gene
A physical unit that corresponds to a section of DNA which codes for a specific mRNA
A physical unit that is passed onto offspring
What is the structure of DNA?
Deoxyribose nucleic acid
Made up of nucleotides
In a double helix
Joined by a sugar-phosphate backbone
Define what a genome is
A genome is all of an organisms DNA
The human genome consists of 3 million base pairs
Each(most?) cell houses our entire genome
How many chromosomes do humans have? How are these divided?
46 chromosomes
23 pairs
22 pairs autosomes
1 pair sex chromosomes
What is an allele?
Genes that occupy the same gene loci on homologous chromosomes
They code for the same trait, but not necessarily the same expression of that trait
What is a genotype?
Is which genes are possessed by someone
What is a phenotype?
The expression of genes
ie the expression of a trait
What is a Wild Type?
_____ is the “normal” allele +
What is a mutant allele?
What does homozygous mean?
Homozygous means that both alleles codes for same expression
so possession of the same Type - WT or Mutant Allele
BB
What does heterozygous mean?
Heterozygous is when one is in possession of two DIFFERENT Allele types
Bb
What does monogenic mean?
Means there is one gene involved
What does polygenic mean?
Means there are multiple genes involved in controlling a trait
There is an influence on the final phenotype
What is phenotype plasticity?
PP is how much a phenotype is determined by environmental factors
Explain the A B O alleles in terms of dominance and recessiveness
A and B are co-dominant
Meaning both expressed when heterozygous
O is the absence of antigen –> recessive
