chap.8 key terms
Terms
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- transmission of genetic traits from parent to offspring
- heredity
- study of heredity
- genetics
- cross involving one pair of contrasting traits
- monohybrid cross
- displaying only one form of a particular trait in offspring
- true-breeding
- the first two individuals that mate in a genetic cross
- P generation
- the first offspring from a cross of two arieties in the parent generation
- F1 generation
- the offspring from crosses among individuals of the F1 generation
- F2 generation
- an alternative form of a gene
- allele
- genetic trait that is expressed when its allele is homozygous or heterozygous
- dominant
- genetic trait that is not expressed when the contrasting form of the triat is present
- recessive
- refers to an individual with two identical alleles for a trait
- homozygous
- refers to an individual with two different alleles for a trait
- heterozygous
- the genetic makeup of an organism as indicated by its set of alleles
- genotype
- observable characteristics of an organism
- phenotype
- first law of heredity stating that pairs of alleles for a trait separate when gametes are formed
- law of segregation
- second law of heredity stating that pairs of genes separate independently of one another
- law of independent assortment
- diagram used by biologists to predict the probable outcome of a genetic cross
- punnett square
- a genetic cross of an individual whose phenotype is dominant but whose genotype is unknown, with a homozygous recessive individual
- test-cross
- the likelihood that a specific event with occur
- probability
- family history that shows how a trait is inherited over several generations
- pedigree
- a trait that is determined by a gene found on the X chromosome
- sex-linked trait
- characteristic of an organism that is influenced by several genes
- polygenic trait
- condition in which a trait in an individual is intermediate between the phenotype of its two parents
- incomplete dominance
- condition in which both alleles for a gene are expressed when pressent
- codominance
- the existence of more than two alleles (versions of the gene) for a genetic trait
- multiple alleles