Maternal and paternal alleles for a trait separate from one another during gamete formation and reunite during fertilization
Law of Segregation (First Law)
During gamete formation, the alleles for different traits segregate independently of one another
Law of Independent Assortment (Second Law)
One dominant allele “masks” the expression of a recessive allele
Law of Dominance (Third Law)
Any inheritance pattern that dooes not follow one or more laws of Mendelian Genetics
Non-Mendelian Genetics
True or False? Double dose of a dominant
allele may be lethal.
True
has hundreds of alleles resulting in four basic phenotypes
PKU(phenylketonuria)
- One allele is not completely dominant over another
- Both traits are expressed
*Traits are blended together rather than occurring distinctly from one another
Incomplete Dominance
Both alleles for a particular trait are expressed equally
Codominance
genotype that causes death before the individual can reproduce.
– Removes an expected progeny class following a specific cross
Lethal Genotypes
- its sequence can deviate in many ways.
- Different allele combinations can produce variations in the phenotype
Multiple Alleles
a gene that affects expression
of another gene
Modifier Gene
- Phenomenon where one gene affects the
expression of a second gene - Interaction of two or more gene pairs at
different loci influence the same trait, but one allele has an overriding effect on the
phenotype
Epistasis
the percentage of individuals who have a
certain genotype and show the expected phenotype
Penetrance
the severity or extent of the phenotype an individual shows
Expressivity
same genotype will produce
different “degrees” of phenotype in
individuals
variable expressivity
Phenomenon where one gene controls several functions or has more than one effect
Pleiotropy
Trait that appears inherited but is caused by the environment
Phenocopy
can enable woman to avoid transmitting a mitochondrial disorder
Ooplasmic transfer technique
What mitochondrial disorder is responsible for weak and flaccid muscles
Mitochondrial myopathies
what mitochondrial disorder is responsible for impaired vision
Leber optical atrophy
Condition where the mtDNA sequence is not the same in all copies of the genome
Heteroplasmy
*Directly violates the Law of Independent Assortment
* Sometimes alleles of certain genes are inherited together, rather than segregating independently
* Genes located in close proximity to each other on the same chromosome are more likely to be inherited together instead of assorting independently
Gene Linkage
group of genes within an organism that was inherited together from a single parent
haplotype
- Traits that are coded for by genes that are
located on the sex chromosomes
– Usually found on the X chromosomes
Sex-linked Traits
