Topic 4b - Inheritance Flashcards
What is Lamarckianism?
changes in condition are passed onto offspring
Years Mendel conducted pea experiments?
1856-1863
Which traits did Mendel choose to work with?
seed shape seed colour flower colour pod shape pod colour flower/seed position stem length
Define progeny…
offspring of mating/breeding
Define F1 generation…
First filial generation (cross between 2 pure breeding strains)
Define F2 generation…
2nd filial generation (progeny of crosses of F1 progeny)
Define dominant…
trait that masks the presence of a recessive trait
Define recessive…
a variant expressed only when a dominant trait is absent
Define the Law of Segregation…
Individuals carry 2 alleles of each gene controlling inherited traits. Alleles partition themselves when gametes form so that each gamete has only one pair of alleles. eg. Gg -> 1G & 1g = 1 ‘green’ allele in one gamete & 1 ‘yellow’ allele in the other gamete
Define genotype…
combination of alleles in an organism
Define phenotype…
the physical/observable characteristic
What does a punnett square predict?
genotypic & phenotypic frequencies
Define pleiotropy…
a single gene controls more than one phenotypic trait
Define incomplete dominance…
phenotype of a heterozygous individual is intermediate between that of each homozygote eg. Red snapdragon + white snapdragon = pink snapdragon
Incomplete dominance ratio?
1 : 2 : 1
An example of co-dominance…
blood type in humans
Which blood types are most to least common…?
A & B (most common), then AB, then O
4 types of cross…
monohybrid
dihybrid
testcross
backcross
In dihybrid crosses, F1 generation shows what? F2 generation?
F1 - all dominant traits
F2 - combination of dominant & recessive traits
Typical dihybrid cross F2 ratio…?
9:3:3:1
Define the law of independent assortment…
Traits don’t affect each other - alleles of one trait assort into gametes independently of alleles of another gene controlling a different trait
Sex-linked traits controlled by…?
sex chromosomes (X or Y)
T or F - environment has no effect on phenotype
false - environment can affect genotype & phenotype
eg. alkaline pH = pink flower, acidic pH = blue flower
