what is genetics?
the study of structure and function of genes
hereditary traits passed from one generation to the next
genetic composition of an organism
observable trait or set of traits
the phenotype is determined by?
interactions of genes and environment. Genes provide potential but environment determines how that potential is realized
who laid the foundations for our current understanding of heredity?
Mendel worked with __
Mendel's success was a result of?
focusing on well-defined traits, quantifying offspring, analyzing result mathematically
why were garden peas so great for research?
they grow easily, produce large numbers of seeds quickly, self-fertilize, cross fertilization is easy
When mendel produced peas using serl-fertilization, this ensured what?
that traits of interest were unchanged in subsequent generation
progeny of the P generation is the __
first filial generation (F1)
When F1 interbreed, we get __
second filial generation (F2)
a monohybrid cross involves ___ that differ in __
true-breeding strains that differ in a single trait
principle of uniformity states that ___. It only applies to ___
In mendelian genetics, offspring of a monohybrid cross will resemble only one parent; only applies to the F1 generation
traits that disappear in the F1 reappear where?
the F2 ratio of reappearing phenotype is __
1 for ever 3 phenotypes in F1 (3:1)
true breeding contain __
Punnett squares show us what?
diagram showing all possible combinations of the gametes produced by each parent
The principle of segregation?
(1st mendelian law) recessive characters that are masked in F1 reappear in a specific proportion in F2.
plants with the recessive phenotype are ___
all true breeding
dominant phenotypes are __ trust breeding and __ produce progeny of both phenotypes
What is a null mutation?
a mutation that results in no protein or a protein with no function
The wrinkled pea phenotype is recessive because of what?
the protein product of its gene is missing or does not function correctly
principle of independent assortment?
Mendel's 2nd law: The factors (genes) for different traits assort independently of one another, which allows for new combinations of the traits in the offspring
a diybrid cross will produce four phenotypic classes in a ___ ratio
involving 3 independently assorted character pairs are "trihybrid". There are 64 combination of 8 different gamete types. Ratio: 27:9:9:9:3:3:3:1
what does a chi square test measure?
the deviation of observed values from expected values; whether differences are due to chance alone
In a chi-square test, what does "P" measure?
the probability that a certain amount of deviation is seen by chance
does a chi square prove a hypothesis?
degrees of freedom=
(# of phenotypes - 1)
if P is 0.05 or less, we ___. If it is higher, we ___
fail to reject; we accept
Who was the first to show Mendelian genetics in humans?
W. Farabee; brachydactyly was a simple, dominant trait
What is brachydactyly ?
a simple dominant trait that results in abnormally broad and short fingers
Pedigree analysis is
the study of phenotypic records of a family over generations
In a pedigree analysis, the individual upon whom the study focuses is the ___ (male) or ___ (female)
In a pedigree analysis, a male is ___ and female is ___. Affected is ___ and not affected is ___.
square, circle. Affected is colored in and not is open.
recessive traits in humans are a result of _?
result of a mutation causing loss or modification of a gene. (albinism)
characteristics of recessive inheritance of a relatively rare trait. Parents of affected are usually heterozygotes and therefore, a carrier.
mating of heterozygotes produce ___ normal and ___ recessive phenotype
In dominant traits, a mutation may produce a dominant phenotype by causing ___
function to be gained
Results from heterozygosity for a dominant mutation in the fibroblast growth factor receptor 3 gene on chromosome 4; Homozygosity is lethal
Dominant alleles produce a distinct phenotype when in a heterozygote whose other allele is ___
Characteristics of recessive inheritance of a relatively rare trait
Affected individuals have at least one affect parent, The trait is present in every generation, Offspring of an affected heterozygote will be ½ affected and ½ wildtype
Autosomal dominant polycystic kidney disease (ADPKD)?
Dominant trait/disorder passed down through families in which many cysts form in the kidneys, causing them to become enlarged
dominant trait and refers to shortening of the fingers or toes due to underdevelopment of the bones in the hands or feet
dominant trait and disorder of connective tissue, the tissue that strengthens the body's structures. Disorders of connective tissue affect the skeletal system, cardiovascular system, eyes, and skin
When calculating probabilities, the product rule is _
The probability of two independent events occurring simultaneously is the product of their individual probabilities.
P(A and B) = P(A) X P(B)
When calculating probabilities, the sum rule is _
The probability of either one of two mutually exclusive, independent events occurring is the sum of their individual probabilities.
P(A or B) = P(A) + P(B)