Allele combinations
the specific pairs or sets of gene variants (alleles) an organism inherits for a particular trait
Single (monohybrid) and double factor-cross (dihybrid) genetic problems
Single (monohybrid) using 2 x 2 squares
Double factor cross (dihybrid) using 4 x 4 squares
Mendel’s law of segregation
paired alleles for a single trait separate during gamete formation, so each gamete gets only one allele, ensuring offspring inherit one from each parent
Law of independent assortment
alleles for different genes sort independently of each other into gametes, meaning the inheritance of one trait doesn’t affect another (for genes on different chromosomes)
Three of dominance relations
incomplete dominance, codominance, and complete dominance
Incomplete dominance
where a heterozygous genotype results in a phenotype that is a blend or intermediate between the two homozygous phenotypes
Codominance
a pattern where both alleles for a trait are fully and equally expressed in the offspring, creating a phenotype that shows both parental traits distinctly, not blended
Complete dominance
where a dominant allele completely hides the effect of a recessive allele in a heterozygous organism
Environmental effects on phenotype
influencing gene expression, leading to variations from the same genes
Continuous variation vs. discrete types
Continuous variation: involves traits with a wide spectrum of phenotypes, influenced by many genes, and environment, forming a bell curve
Discrete types: involves traits with distinct, separate categories, controlled by one or few genes, showing no intermediates
Loci
the specific, fixed physical location of a gene or DNA sequence on a chromosome
Alleles
a variant or alternative form of a specific gene, existing at the same location (locus) on a chromosome
Dominant
a trait or allele that masks another trait, appearing in the organisms phenotype even if only one copy is present
Recessive
a genetic factor that only expresses its trait when two copies are inherited, one from each parent
Homozygous
having two identical alleles for a specific gene, one inherited from each parent, resulting in a consistent genetic makeup that strongly influences inherited traits or genetic conditions
Heterozygous
having two different alleles for a specific gene, one inherited from each parent
Genotype
an organism’s specific makeup, referring to the alleles it carries for particular traits
Phenotype
the set of observable characteristics of an individual resulting from the interaction of its genotype with the environment
Probability
the measure of likelihood of an event occurring
Carrie
an organism that carries a gene or trait or disease but shows no symptoms, while also being able to pass that gene to offspring
Epistasis
when on gene masks, modifies, or suppresses the expression of another, non-allelic gene, leading to altered phenotype traits than what standard mendelian genetics predict
Polygenic inheritance
when a single trait, like height or skin color, is controlled by the addictive effects of multiple genes
Multiple alleles
a situation where a single gene has three or more different versions (alleles) within a population
Punnett square
a square used to predict the probable genetic makeup
