Chapter 2: Mendelian Inheritance Flashcards
Why did Mendel chose to study pea plants?
Their ability to carry out self-fertlization or cross fertlization
Several varieties which a character existed in two distinct variants
A Punnett square is used to predict the outcome of a __-__ cross and __-__ experiment
single-factor; self-fertilization
What were the three key ideas Mendel proposed regarding inheritance?
Traits may be dominant or recessive
Genes are passed unaltered from generation to generation
Law of segregation
Describe the Law of Segregation.
two copies of a gene segregate (or separate) from each other during transmission from parent to offspring
Describe the Law of Independent Assortment
Two different genes will randomly assort their alleles during the formation of haploid cells
A Punnett square can also be used to predict the outcomes of a __ factor cross
two
Which method should you use for solving the outcomes of crosses involving three or more genes?
forked-line methods
Describe the product rule.
finds the probability that two or more independent outcomes will occur is equal to the product of their individual probabilities
The binomial expansion equation is used to predict the probability of?
a given set of two unordered outcomes
What is the chi square test used for?
To determine the validity of a hypothesis
What are the two most prominent theories of inheritance that have been proposed?
Theory of Pangenesis
Theory of Preformationism
What is the Theory of Pangenesis?
genetic information (gemmules) travel from different parts of the body to the reproductive organs where it is transferred to gametes
What is the Theory of Preformationism?
homonuculus
Blending theory states that?
hereditary traits can blend together generation after generation
Mendel chose to study _ different traits
seven
What is the difference between cross-fertilization and self-fertilization?
cross: pollen and egg from different plants
Self: pollen and egg from same plant
Mendel found a : ration when performing a monohybrid cross.
3:1
Mendel’s data suggested which theory?
Particulate theory of inheritance
What did Mendel postulate after the 3:1 ratio monohybrid cross?
two discrete hereditary factors (alleles) from each parent
may be homo or hetero
can be dom or recessive
law of segregation
randomized process
Define a genotype
specific allelic composition of an individual (i.e. TT; Tt; tt)
Define a phenotype
the physical appearance of an individual
(i.e tall or short)
The phenotype is a product of the __ and the __
genotype; environment
How did Mendel verify his principle of segregation?
Test cross
Describe a test cross
an organism w a known phenotype but unknown genotype is crossed w an organism that has the recessive phenotype (homo recess)
What is the predicted phenotypic ratio of independent assortment?
9:3:3:1
Define a loss-of-function allele
an allele that encodes an RNA or protien that is nonfunctional or compromised in function
What is the benefit of loss-of-function alleles?
Modern genetic testing/ understanding
What is the one caveat to using the forked line method?
genes must not be linked
If n=# of heteroxygous gene pairs involved
Number of possible gametes =
Number of different genotypes in zygotes=
Number of different phenotypes in zygotes=
Proportion of homozygous recessive in F2=
2^n
3^n
2^n
(1/4)^n
The product rule deals with __ events
independent
The sum rule deals with __ events
mutually-exclusie
How can I use the sum rule if two events are not mutually exclusive?
P(A or B) = P(A) + P(B) - [P(A) x P(B)]
The 3:1 and 9:3:3:1 rations are based on what four assumptions?
Dominance/ recessiveness of alleles
Complete segregation
Independent assortment
Random fertilization
What is the chi-square test used for?
determines ‘goodness of fit’
A low chi square value indicates a __ probability that the observed deviations could be due to random chance alone
high
A high chi square value indicates a __ probability that the observed deviations are due to random chance alone
high
