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gene that produces its characteristic phenotype only when its allele is identical


the version of genes someone has. (Not visible)


two different versions of that trait


two of the same trait


gene that produces the same phenotype in an organism whether or not the allele is identical


method of determining genotype

Monohybrid experiments

testcrosses that check for a dominance relationship between two alleles at a single locus

Punnett Squares

used to calculate the probability of a genotype

Law of Segregation

"Diploid cells have pairs of genes, or pairs of homologous chromosomes. The two genes of each pair are separated from one another during meiosis, so they end up in different gametes."

Dihybrid crosses

done to determine dominance relationship between alleles at two loci

law of Independant Assortment

"Genes are sorted into gametes independently of other genes"


two nonidentical alleles of a gene are both fully expressed in heterozygotes, so neither is dominant or recessive

Incomplete Dominance

one allele of a pair isnt fully dominant over its partner, so heterzygote's phenotype is between that of the homozygotes


Interactions between different gene products.


one gene that influences multiple traits


fibers that give elasticity to tissues of heart, skin, blood vessels, tendons, and other body parts.

Linkage Groups

all genes on a chromosome


enzyme that affects the coat color of Himalayan rabbits

Continuous Variation

other traits that occur in a range of small differences

bell curve

the type of curve if a trait shows continuous variation


finger shape and movement are abnormal


diagnostic tool that helps determine the individual's diploid set of chromosomes


cartilage model of skeleton doesnt form properly. caused by an autosomal dominant allele

Huntington's Disease

involuntary muscle movements increase as nervous system deteriorates. Caused by an autosomal dominant allele


Malnutrition, diarrhea, vomiting, damage to eyes, liver and brain, eventual death. caused by a recessive autosomal inheritance


mutated allele produces hutchinson-gilfork progeria syndrome. accelerated rate of aging and short life span.

Hemophilia A

x-linked recessive disorder; interferes with blood clotting.

Duchenne Muscular Dystrophy

muscle degeneration. genes of X encodes dystrophin, structural/support protein muscle cells


normal chromosomes have DNA sequences that are duplicated several times


loss of some portion of a chromosome


(cry of the cat) deletion of chromosome 5 causes mental impairment and an abnormally shaped larynx


part of the DNA sequence within the chromosome becomes oriented in the reverse direction, with no loss


part of a broken chromosome attaches to a different chromosome or to a different part of the same one


cells that normally have 3+ types of each chromosomes


1+ pairs of chromosomes do not seperate properly during mitosis or meiosis

Down syndrome

only tricomis individuals who reach adulthood. upward slanting eyes, deep crease across sole of foot and palm of hand. moderate to severe mental impairment and heart problems

Klienfelter's syndrome(XXY)

outcome of nondisjunction. feminizing effects: small testes and prostate glands, low sperm count, sparse body hair, enlarged breasts

XYY syndrome

taller than average, mild mental temperament


before birth


up to 8 weeks after fertilization


8+ weeks after fertilization


a syringe withfraws 20mL of amniotic fluid, which contains shed fetal cells and fetal waste

genetic screening

routine testing for alleles associated with genetic disorders. provides info on reproduction risks

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