Chapter 14 Flashcards
character
A heritable feature that varies among individuals (such as flower color)
trait
Each variant for a character (ex. purple or white color for flowers)
advantages of using peas
Short generation time Large numbers of offspring Mating could be controlled to self-pollinate or cross pollinated
true breeding
plants that produce offspring of the same variety when they self-pollinate
hybridization
He mated two contrasting, true-breeding varieties
P generation
The true-breeding parents
F1 generation
The hybrid offspring of the P generation
F2 generation
When F1 individuals self-pollinate or cross- pollinate with other F1 hybrids
alleles
alternative versions of a gene
account for variation in inherited characteristics
reside at a specific locus on a specific chromosome
where do alleles for each character come from?
one from each parent
law of segregation
the two alleles for a heritable character separate (segregate) during gamete formation and end up in different gametes
Egg or a sperm get only one of the two alleles that are present in the organism
law of independent assortment
It states that each pair of alleles segregates independently of each other pair of alleles during gamete formation
This law applies only to genes on different, nonhomologous chromosomes or those far apart on the same chromosome
Genes located near each other on the same chromosome tend to be inherited together
complete dominance
occurs when phenotypes of the heterozygote and dominant homozygote are identical
incomplete dominance
the phenotype of F1 hybrids is somewhere between the phenotypes of the two parental varieties
codominance
two dominant alleles affect the phenotype in separate, distinguishable ways
types of blood
IAIA or IAi=A
IBIB or IBi=B
IAIB=AB
ii=O
pleiotropy
Most genes have multiple phenotypic effects
epistasis
a gene at one locus alters the phenotypic expression of a gene at a second locus
example of epistasis
For example, in Labrador retrievers and manyother mammals, coat color depends on two genes
One gene determines the pigment color (with alleles B for black and b for brown)
The other gene (with alleles E for color and e forno color) determines whether the pigment will be deposited in the hair
quantitative characters
are those that vary in the population along a continuum
polygenic inheritance
additive effect of two or more genes on a single phenotype
skin color
multifactorial
Traits that depend on multiple genes combined with environmental influences
what does phenotype include?
An organism’s phenotype includes its physical appearance, internal anatomy, physiology, and behavior
An organism’s phenotype reflects its overall genotype and unique environmental history
why are humans bad subjects for genetic research?
Generation time is too long
Parents produce relatively few offspring
Breeding experiments are unacceptable
