PROBABILITY AND STATISTICS IN GENETICS Flashcards
can be used to
predict the outcomes of genetic crosses
laws of inheritance
are concerned
with the types of offspring produced from
their crosses
Animal and plant breeders
___ are interested in predicting the
traits that their children may have. This is particularly important in the case of families with___.
Parents
genetic diseases
However___ can help
couples by predicting the likelihood of them having an affected child
genetic counselors
This probability may influence the couple’s decision to
have children or not
The ____ of an event equals the number of times it happens divided by the number of opportunities.
probability definition
The numbers of a probability of an event can be determined by
____ and ____.
experiment or by knowledge of the
system.
The value of studying genetics is in
understanding how we can predict the likelihood of inheriting particular traits.
Basic Principles of Genetics Probability of Inheritance
This can help plant and animal breeders in developing varieties that have more _____.
desirable qualities.
It can also help people ____ and ____ patterns of inheritance in family lines.
explain and predict
One of the easiest ways to calculate the mathematical probability of inheriting a specific trait was invented by an ____
early 20th century English geneticist named Reginald Punnett.
Reginald Punnett. His technique employs what we now call a ____.
Punnett square.
a simple graphical way of discovering all of the potential combinations of ____ that can occur in children, given the ___ of their parents.
genotypes
It also shows us the odds of
each of the ____ occurring.
offspring genotypes
Why is it important for you to know about Punnett squares?
predictive tools when considering having children.
If both parents are carriers of the recessive allele for a disorder, all of their children will face the following odds of inheriting it:
____ chance of having the recessive disorder
____ chance of being a healthy carrier ____ chance of being healthy and not have the recessive allele at all.
25%
50%
25%
If a carrier (Aa) for such a recessive disease mates with someone who has it (aa), the likelihood of their children also inheriting the condition is _____.
far greater
If one parent is a carrier and the other has a recessive disorder, their children will have the following odds of inheriting it:
___ chance of being a healthy carrier
___ chance having the recessive
disorder
50%
50%
In addition to ____, _____, and ____ are recessive disorders.
cystic fibrosis, albinism, and
beta-thalassemia(severe anaemia)
Some disorders are caused by _____ for genes.
Inheriting just one copy of such a _____ allele will cause the
disorder.
dominant alleles, dominant
dominant allele will cause the
disorder. This is the case with
Huntington disease,
achondroplastic dwarfism, and polydactyly.
If only one parent has a single copy of a dominant allele for a dominant disorder, their children will have a ____ chance of inheriting the disorder and
____ chance of being entirely normal.
50%
50%
If P is = 0, then the event is ____.
impossible
It is also possible to determine probability by experiment:
if the die were) ____.
unbalanced
Probability is expressed in numbers between ___ and __.
0 and 1.
Probability = 0 means the event ____; probability
= 1 means it ____.
never happens
always happens.
The total probability of all possible event always sums to __.
1.
The accuracy of the probability prediction depends largely on the _____.
size of the sample.
Often, there is ____ between observed and expected outcomes. This is due to _____.
deviation
random sampling error.
Random sampling error is ______,
and small for ______.
large for small samples
large samples
Probability calculations are used in genetic problems to ____.
predict the outcome of crosses.
To compute probability, we can use three mathematical operations
Sum rule
Product rule
Binomial expansion equation
indicates the need to add
THE SUM RULE (“OR” RULE)-
The probability that either one of 2 different events will occur is the ___ of their separate probabilities.
sum
This rule can be used to calculate the probability of an event when the event of interest can be one of two or more events
THE SUM RULE (“OR” RULE)
Can only be used for mutually exclusive events
THE SUM RULE (“OR” RULE)
formula of THE SUM RULE (“OR” RULE)
P(event A or event B) =P(A) + P(B)
Two events are _____ if the occurrence of one excludes the occurrence of the other
mutually exclusive
Two events are _____ if the occurrence of one does not affect the probability of the other.
independent
= p(A ” and “A) “or” p(A “and “a)
= p(A x A) + p(A x a)
indicates the need to multiply
THE PRODUCT RULE (“AND” RULE)-
When two or more events occur
independently of one another, but at the same time, we can calculate the probability of possible outcomes when they occur together
THE PRODUCT RULE (“AND” RULE)
P (event A and event B) =
P(A) x P(B)
Can only be used for independent events
THE PRODUCT RULE (“AND” RULE)-
indicates the need to add
AT LEAST” STATEMENT:
= p(3 out of 5) “or” p(4 out of 5)”or” p (5 out of 5)
= p(3 out of 5) + p(4 out of 5)”or” p (5out of 5)
indicates the need to use the formula for combinations.
THE BINOMIAL FORMULA (COMBINATION STATEMENTS):
The binomial formula can determine ____
probabilities of sets of events
It is applicable in a very specific circumstances
THE BINOMIAL FORMULA (COMBINATION STATEMENTS):
Apply this formula when you want the probability that a set
of events will consist of so many of one type of event and so
many of another type of event, and the order of the events
does not matter
THE BINOMIAL FORMULA (COMBINATION STATEMENTS):
If the order does matter, the ______ is usually the way to do
product rule
Each of the events in the set can have only ___ possible outcomes
two
In Binomial Formula, n indicates ____.
total number of events
In Binomial Formula, p indicates ____.
number of 1 kind (type A events)
In Binomial Formula, q indicates ____.
number of the alternative (type B events)
In Binomial Formula, r indicates ____.
probability of p occurring (probability of Type A event)
In Binomial Formula, s indicates ____.
probability of q occurring (probability of Type B event)
Evaluates the influence of chance on genetic data.
CHI-SQUARE ANALYSIS-
X2 values greater than those shown at p = 0.05 the null
hypothesis
Failing to reject, the observed deviation are attributed
to chance
X2 values lesser than those shown at p=0.05 the null
hypothesis
-reject the null hypothesis
If fail to reject- the observed deviation froms expected is
not attributed to _____ ; there is a need to
re-examine.
chance alone
