Ch. 11 Flashcards
Who was Gregor Mendel?
a monk who developed his theory of inheritance using pea plants
published his findings in 1866
What is a character?
an observable feature that may vary among individuals
What is a trait?
one of two or more detectable variants in a genetic character
What is true-breeding?
refers to organisms that produce offspring of the same variety over many generations of self-pollination
What is hybridization?
the mating of 2 true-breeding varieties
What is the P generation?
refers to the parental generation
What is the F1 generation?
the first filial, hybrid (heterozygous) offspring arising from a parental cross
What is the F2 generation?
the offspring resulting from interbreeding (self-pollination) of the hybrid F1 generation
What is the first component to Mendel’s model?
alternative versions of genes account for variations in inherited characters
What is the second component to Mendel’s model?
for each character, an organism inherits two versions (two alleles) of a gene, one from each parent
What is the third component of Mendel’s model?
- if the 2 alleles at a locus differ, then the dominant allele determines the organism’s appearance
- the recessive allele has no noticable effect on appearance
What is the fourth component of Mendel’s model?
the Law of Segregation states that the two alleles in a pair segregate into different gametes during gamete formation
What are alleles?
- any of the alternative versions of a gene
- may produce distinguishable phenotypic effects
What are dominant alleles?
alleles that are fully expressed in the phentotype of a heterozygote
What are recessive alleles?
allelles whose phenotypic effects are not observed in a heterozygote
What is a heterozygote?
an organism that has 2 different alleles for a gene
What is a homozygote?
an organism that has a pair of identical alleles for a gene
What is genotype?
the genetic makeup, or set of alleles, of an organism
What is phenotype?
the observable physical and physiological traits of an organism
What is a testcross?
breeding an organism of unknown genotype w/ a homozygous recessive individual to determine the unknown genotype
What does the Law of Independent Assortment state?
“alleles of 2 or more differetn genes get sorted into gametes independently of one another”
What is complete dominance?
the phenotypes of the heterozygote and dominant homozygote are indistinguishable
What are testcrosses used for?
to identify whether an organism exhibiting a dominant trait is homozygous or heterozygous for a specific allele
What is incomplete dominance?
the phenotype of heterozygotes is intermediate between the phenotypes of individuals homozygous for either allele
3 phenotypes exist w/ this condition
What is codominance?
the phenotypes of both alleles are exhibited in the heterozygotes b/c both alleles affect the phenotype in separate, distinguishable ways
2 alleles exist w/ this condition
What are the 4 human blood groups?
A, B, AB, O
Which blood type is the universal donor?
type O
ii genotype, anti-A & anti-B antibodies
Which blood type is the universal receiver?
type AB
I^AI^B genotype, no antibodies
What is the genotype for blood type A?
I^AI^A or I^Ai
anti-B antibodies
What is the genotype for blood type B?
I^BI^B or I^Bi
anti-A antibodies
What is pleiotropy?
the ability of a single gene to have multiple effects
pleiotypic effect: 1 gene = many traits
What is polygenic inheritance?
an additive effect of 2 or more genes on a single phenotypic character
polygenic effect: many genes = 1 trait
