Mendelian Inheritance Flashcards
(30 cards)
What are genetics?
the study of heredity, how inherited variation is encoded, replicated, and expressed, and how it evolves over time. This definition encompasses the three major subdivisions of genetics: transmission
genetics, molecular genetics, and population genetic
Why was Mendel succesful discoveries?
- Had an experimental approach
- He always interpreted his results by using mathematics.
- He was adept at seeing patterns in detail and was patient and thorough, conducting his experiments for 10 years
Advantages of using peas?
- Garden pea plants complete entire generation in a single growing season (annual plants) and produce
many offspring.
▪ Garden pea plants are known to differ in detectably distinct characters. e.g., seed colour, seed shape,
flower colour, pod colour, texture.
▪ Pea plants are self fertilizing plants – True breeding/Homozygous lines. Also, artificial cross-pollination was
possible.
▪ The loci for any two characters studied simultaneously in a dihybrid cross were located far apart in most
cases – Independent assortment.
▪ In Mendel’s peas, the genotype and not the environment, largely determined the characters
What is the chromosomal theory of heredity
What is a monohybrid cross?
the crosses
between parents that differed in a single characteristic using
artificial cross-pollination. (one gene)
What is Mendel’s first law?
Principle of segregation:
This principle states that each individual possesses two alleles (diploid organism) for any particular trait, one
inherited from the maternal parent and one from the paternal parent. These alleles segregate from each other
at the time of gamete formation.”
What is a gene?
What is a llcus
Specific place on a chromosome occupied by an allele
Allele
One of two or more alternative forms of a gene
Genotype
Set of alleles possessed by an individual organism
Homozygote
An individual organism possessing two of the same
alleles at a locus
Heterozygote
An individual organism possessing two different
alleles at a locus
Characteristic or character
An attribute or feature possessed by an organism
Phenotype or trait
The appearance or manifestation of a characteristic
Punnett square
a shorthand method of predicting the genotypic and
phenotypic ratios of progeny from a genetic cross.
Made by R.C Punnet
Backcross
It is a cross between an F1 genotype and either of the parental genotypes
When is a backcross done?
in artificial selection to have organisms with desirable
traits
Testcross?
Testcross is a type of backcross.
In this cross, one individual of unknown genotype is crossed with another individual
with a homozygous recessive genotype for the trait in question.
When is a testcross done?
A testcross helps to test or reveal the genotype of the first individual
What is probability?
Probability refers to the likelihood of the occurrence of a particular event (t is the number of times that a particular event takes place, divided by the number of
all possible outcomes)
2 probabilty rules?
Sum and product rule
Dihybrid cross
crosses in
which the varieties of peas differed
in two characteristics, called
dihybrid crosses.
Principle of independant assortment
that alleles at different loci separate independently of one another.
What does the Chi squared test determine?
This test indicates the likelihood of chance that could produce the deviation between the expected and the
observed values
