Genetics Flashcards
Gene
Genetic Material (RNA or DNA) coding for a single gene product ( Peptide, rRNA, tRNA)
Locus
The chromosomal Location of a gene
Allele
One Variant of a gene. Eye color alleles will code for the same trait but one may code for brown and the other may code for blue
Homologous Chromosomes
Chromosomes that code for the same set of genes (but may have different alleles) one received from each parent
How many chromosomes in humans?
46 chromosomes, 23 pairs. 1 pair related to gender
Law of Segregation
Separation of alleles in haploid gametes. Mendel. We are diploid but they separate in your gametes
Law of Independent Assortment
Genes assort independently to the progeny. Linkage violates this
Complete Dominance
When a Heterozygote has the phenotype of 1 of the alleles (the dominant one)
incomplete dominance
phenotypes of progeny are blends of the parental phenotypes. Black person and White person will have Tan kids
Codominance
Both inherited alleles are completely expressed. Blood types ABO
Pleiotropism
When a gene has multiple phenotypes associated with its expression
polygenism
when multiple genes affect a trait. Opposite of Pleiotropism
Penetrance
Probability of an organism with a specific genotype will express a specific phenotype.
Expressivity
Term describing the variation of a phenotype for a specific genotype. (degree of yellowness, dark-light)
Epistasis
Occurs when the expression of a gene us dependent upon another gene. Gene for red hair dependent on gene for male pattern baldness. Can’t have red hair if you’re bald.
Which sex is responsible for determining sex of child
father. Can only get an X from mom, Can get either an X or Y from dad.
Colorblindness
X-linked recessive. Usually only present in males
Mitochondria
Have own DNA/ribosomes. All from Mother
Turner’s Syndrome
1 sex chromosome X. Develops as female, results from nondisjunction.
Kleinfelter’s syndrome
3 sex chromosomes. XXY. Male. nondisjunction
Point Mutations
Substitution, insertion, deletion. Change of single nucleotide.
Missense Mutation
Point mutation leading to a codon coding for a different amino acid (substitution). Could be deleterious or not. If you change out one non polar AA for another non polar one it’s ok. If you swap it with a charged AA it could be bad. 3rd base of codon not a big deal.
nonsense mutation
point mutation leading to a stop codon
frameshift mutation
insertion or deletion leading to a change in the reading frame of a gene. Add one or remove one nucleotide. Causes major changes, almost always deleterious.
