Terms in this set (42)
what is a heritable feature that varies among individuals?
what is the term for variations in character?
what is true-breeding?
an organism that has expressed the same trait for many generations
what is the cross breeding of two true breeding organisms?
what are the true-breeding parents called in hybridization?
P generation (parental)
what is the first generation of two true-breeding organisms called?
F1 generation (filial from latin word for son)
What is the second generation of organisms from true-breeding parents?
what are alternative versions of genes called?
what determines the appearance of a gene?
the dominant allele
what allele has no noticeable effect on the organism's appearance?
the recessive allele
what is the law of segregation?
the two alleles for a heritable characteristic segregate from each other during gamete formation and end up in different gametes
if an organism has one recessive and one dominant allele how are the genes distributed?
50% of gametes get dominant, 50% get recessive
what is homozygous
an organism that has identical alleles for a certain characteristic
what is heterozygous?
an organism that has two alleles for one trait
what is a phenotype?
the expressed trait that is visible. Physiological
what is a genotype?
the genetic makeup of a trait
do Pp and PP plants have the same genotype or phenotype?
What is it called when you test an organism with an unknown genome with a recessive homozygote?
what are monohybrids?
heterozygous for the one particular trait being followed
what is the breeding between heterozygotes?
what is it called when an organism is heterozygous for two characteristics being followed?
what is dependent assortment?
when an organism has two traits that are always expressed together. like Yellow wrinkled is TOGETHER dominant
what is the law of independent assortment?
Two or more genes assort independently
What must be true for the law of independent assortment to be true?
applies only to alleles located on different chromosomes that are not homologous or on genes very apart from each other on the same chromosome
What is complete dominance?
when a recessive or dominant allele is completely expressed in a phenotype
What is incomplete dominance?
When neither of the alleles are completely dominant and make a hybrid of the phenotypes
what is codominance?
when both alleles are dominant. They both effect the phenotype in separate, distinguishable ways
why is an allele called "dominant"
because it is expressed in the phenotype
When an organism is heterozygous for a trait, is the recessive trait expressed?
not explicitly, but it can be seen as codominance if examed very closely
what is the condition in which children have more than the normal amount of fingers or toes? What is this due to?
polydactyly. When a dominant gene is expressed. The normal population has more recessive alleles than dominant
what is the genotype for AB blood type?
what is the genotype for O blood type?
what is pleiotrophy?
have multiple phenotypic effects such as characteristics of a disease
what is epistasis?
when the phenotypic expression of one gene affects the expression of another gene on another locus. The two interact. Example of coat color
what is polygenic inheritance?
the more of a group of genes, the more the phenotype is expressed
are phenotypic traits normally static and unchangeable? What is this called?
no, can change with the environment. Multifactorial. Both genetic and environmental factors affect phenotype
what is an autosomal recessive condition?
requires two recessive alleles to have the condition
what is an autosomal dependent condition
need to only have one dominant allele to have condition. Those unaffected must have two recessive alleles
what is the expected ratio for a dihybrid cross?
what is an example of polygenic expression?
height or skin color
what is a pedigree?
a family tree that describes interrelationships of parents and children across generations
what are carriers?
heterozygous organisms which carry a recessive allele but do not have phenotype