Lesson 3 : TRANSMISSION GENETICS Flashcards
Father of Genetics
GREGOR MENDEL
Gregor Mendel conducted experiments from ____ to _____ on traits in _______ plants.
1857 to 1863
24,034
In ____s Gregor Mendel discovered the
______________ by breeding _________.
fundamental principles of genetics
garden peas
Mendel’s first law of inheritance
LAW OF SEGREGATION
Another term for the LAW OF SEGREGATION
Law of Gene Segregation
What does the Law of Segregation states
It states that alleles segregate randomly into gametes. Such that half of the parents’ gametes carry each allele.
PEAS WERE IDEAL DUE TO THE FOLLOWING
FACTORS:
● Easy to grow.
● Develop quickly.
● Have many traits that take one of two easily distinguishable forms.
it is the characteristics outside or outside distinguishable expression of an organism.
Phenotype
HIERARCHY OF GENETIC CROSSES
● P1 - first generation or parenteral generation.
● F1 - second generation or the first filial generation.
● F2 - third generation or the second filial generation.
TYPES OF BREED
● True-Breeding
● Monohybrid Cross
● True-Breeding
○ Offspring have the same trait as parents.
○ The observed trait is dominant.
○ The masked trait is recessive.
● Monohybrid Cross
○ Follows one trait.
○ Is a cross of two heterozygous individuals for a single trait.
TERMS AND TOOLS TO FOLLOW SEGREGATINGGENES
● Homozygous
● Heterozygous
● Genotype
● Phenotype
● Wild Type
● Homozygous
○ Carry same alleles TT or tt.
● Heterozygous
○ Carry different alleles Tt.
○ Non-true breeding or hybrid.
● Genotype
○ Organism’s alleles.
● Phenotype
○ Outward expression of an allele combination.
● Wild Type
○ Most common phenotype in a population for a particular gene (Dominant or Recessive).
A _________ illustrates how alleles combine in offspring.
Punnett Square
Helps identify if the breeding is true-breeding or non-true-breeding.
TEST CROSS
A ________ controls trait transmission, but other genes and the environment affect the ___________ or __________.
single gene
degree of the trait or severity of the illness
When one parent has an autosomal dominant condition and the other does not, each offspring has a ______ probability of inheriting the _________ and _________.
50%
mutant allele
the condition
CRITERIA FOR AUTOSOMAL RECESSIVE TRAITS
● Males and females can be affected.
● Affected males and females can transmit the gene, unless it causes death before reproductive age.
● Trait can skip generations.
● Parents of an affected individual are heterozygous or have the trait.
● Conditions likely to occur in families with consanguinity.
Define Consanguinity
you are closely related to each other
DOMINANCE AND RECESSIVENESS
● Dominance
○ Gain of function
● Recessive
○ Loss of function
What does the LAW OF INDEPENDENT ASSORTMENT
state
States that the alleles of two or more different genes get sorted into gametes independently into each other.
The likelihood that an event will occur.
PROBABILITY
Probability of simultaneous independent events equals the product of their individual probabilities.
Product rule
are symbolic representations of family relationships and the transmission of inherited traits.
Pedigrees
A partial pedigree of Egypt’s Ptolemy dynasty showing:
○ Genealogy not traits
○ Extensive inbreeding
Deficiency in melanin production
Albinism
Parents are inferred to be heterozygous
AUTOSOMAL RECESSIVE TRAIT
Does not skip generations, can affect both sexes.
AUTOSOMAL DOMINANT TRAIT
extra fingers and/or toes.
Polydactyly
This pedigree can account for either an autosomal dominant or an autosomal recessive trait.
INCONCLUSIVE PEDIGREE
Pedigrees and Punnett squares apply Mendel’s laws to predict the recurrence risks of inherited conditions
CONDITIONAL PROBABILITY
