Mendel Gene Idea Flashcards
Why did medel choose to work with peas?
Different observable traits
Strict control over plant mating
Cheap and readily available
They grow fast
What is hybridization?
Mating of two true-breeding varieties
true breeding is a plant when self fertilized only produces offspring with the same traits
What are dominant traits?
trait that recurrs most often
Wht are recesive traits?
traits that occur less often
What are alleles?
variations in a genes nucleotide sequence, they reside at specific locus on chromosomes
how many alleles make up a triat?
2, one from each parent
if two different alleles occur, what determines the appearance
the dominant trait
What is the law of segregation?
two alleles for a heritable charachter separate during gamete formation and end up in different gametes. egg or sperm only gets one of the two alleles per trait
What is a punnett square?
A diagram for predicting the results of a genetic cross
What is homozygous?
An organism with two identical alleles for one gene
considered to be true breeding
What is heterozygous?
an organism with 2 different alleles for a chracter
heterozygotes are not true breeding
What is a phenotype?
Physical appearance, internal anatomy, physiology, behaviour
What is a genotype?
The genetic makeup of an organism
can have same phenotype but different genotype
What is the law of independant assortment
each trait (2 alleles) are assorted independantly to the gametes
What is complete dominance?
When phenotypes of the heterozygote and dominant homozygote are identical
What is incomplete dominance?
The phenotype of F1 hybrids is somewhere between the phenotypes of the two parents
Parents are Red and White, F1 is pink
when two traits are not completely dominant over the other…. blending of traits
What is Co-dominance?
two dominant alleles affect the phenotype in separate, distinguishable ways. both traits are equally dominant
cows, blue healers
WHat is epistasis?
when two or more genes affect one phenotype
expression of one gene interferes with the expression of another gene
What is pleiotropy?
The ability of a single gene to have multiple phenotypic effects
one gene can influence a combination of seemingly unrelated characteristics
ex. tigers and siamese cats–> gene controlling fur pigment also influences connections between eyes and brain
What is norm of reaction?
Phenotypic range of a genotype influenced by the environment
What is a pedigree?
Family tree describing interrelationships between parents and children across generations
How do recessively inerited disorders show up?
When the recessive trait is homozygous
heterozygous individuals can carry a reccessive trait without it showing
