Chapter 2 - Mendelian Genetics Flashcards
alternative form of a gene
allele
contain like genes for any character
homozygous
contains two kinds of genes for an allelic pair
heterozygous
- appearance or assemblage of characters that are expressed
- may change because of interactions with environment and other genes
phenotype
phenotype formula
P = G + E + (G X E)
- genetic constitution of an individual
- constant
genotype
trait that is expressed in the heterozygote
dominant trait
hidden in the heterozygote
recessive trait
why is mendelian genetics classical
principles of the Mendel still applies until today
what do Mendelian genetics deal with
qualitative traits
- also known as alleles
- According to him, two factors are needed for a trait to be expressed
- allele is one of the possible forms of a gene
- Most genes have two alleles, a dominant allele and a recessive allele
Mendelian inheritance factors
long version of the word allele
allelomorphic pairs
Mendelian genetics criteria
- diploid
- sexually reproducing
- point of attachment of the kinetochore
- attachment of sister chromatids
- site for the attachment of spindle fibre
- help in the proper alignment and segregation of the chromosomes during the process of cell division in eukaryotic cells
centromeres
physical location of a gene on a chromosome
gene loci
- study of how your behaviors and environment can cause changes that affect the way your genes work
- reversible and do not change your DNA sequence
- change how your body reads a DNA sequence
Epigenetics
father of Genetics
Gregor Mendel
Gregor Mendel is the father of __
Genetics
what did Mendel develop
fundamental laws of heredity
what did Mendel blend
Concept of Inheritance vs Particulate Theory of Inheritance
what are the test subjects of Mendel
garden peas
garden peas
Pisum sativum
why did he choose garden peas
- easily grown
- pollination is easily controlled
how did Mendel control pollination
manually moving pollen between plants
what did Mendel develop in garden peas
true-breeding plants by self-pollination
true breeding other term
pure breeding
what does true-breeding or pure-breeding plants mean
homozygous
male parts of flower
anthers
contain sperm
pollen grain
female parts
pistil
eggs
ovule
produce pollen grains, which contain male gametes
anthers
receives pollen
stigma
produce female gametes
ovules
process of Cross-pollination
- remove anthers from one plant
- collect pollen from a different plant
- transfer pollen to stigma of the 1st plant (plant without anthers)
kind of crossing strategy between a pair of parents (A and B) by using them in turn as female parent and male parent to obtain two reciprocal crosses of A×B and B×A
Reciprocal cross
first half of reciprocal cross
pollen from round-seeded to stigma of wrinkled-seeded
second half of reciprocal cross
pollen from wrinkled-seeded to stigma of round-seeded
Why was Mendel successful
- unbiased
- selected good model organism
- used pure breeds as parents
- large sample size
- quantitative analysis
- controlled experiments
- studied obvious traits
Characters which Mendel used
- seed shape
- seed color
- flower color
- pod shape
- pod color
- flower position
- stem height
seed shape
- spherical
- wrinkled
seed color
- yellow
- green
flower color
- purple
- white
pod shape
- inflated
- constricted
pod color
- green
- yellow
flower position
- axial
- terminal
stem height
- tall
- dwarf
a model system not only for studying numerous aspects of plant biology, but also for understanding mechanisms of the rapid evolutionary process associated with genome duplication and polyploidization.
Arabidopsis
Mendel’s conclusions
- genes do not blend together
- peas have two versions, or alleles, of each gene
- each gamete contains one allele of each gene
- males and females contribute equally to the genotype of their offspring
- some alleles are dominant to others
act of castrating (= removing the male sexual parts of) a man or male animal, or removing the male parts of a plant
emasculation
- alleles occur in pairs and that in the formation of gametes, these segregate so that only one member of a pair goes into a particular gamete
- covers how alleles of the same gene assort into different gametes
- monogenic trait
Law of Segregation
trait produced by the effect of a gene or an allele
monogenic trait
descendant or the descendants of a person, animal, or plant; offspring
progeny
original pair of parents at the start of a genetic cross experiment
P generation
first generation that is produced by the p generation
F1 generation
obtained by crossing F1 generation
F2 generation
P generation
parental generation
F1 generation
first filial generation
involves one (mono) character and different (hybrid) traits
monohybrid cross
tool for calculating genetic probability
Punnett squares
- based on dihybrid crosses where two genes are considered simultaneously
- alleles in different gene pairs separate cleanly from each other and randomly combine during gamete formation
- inheritance of one pair of genes is independent of inheritance of another pair
Law of Independent Assortment
made when phenotypes and genotypes composed of 2 independent alleles are analyzed
dihybrid crosses
Mendelian disorders in humans
- ptosis
- progeria
- achondroplasia
- polydactyly
- drooping of the upper eyelid, and the patient usually presents with the complaint of the defect in vision and cosmesis
- can be congenital or acquired, or it can be neurogenic, myogenic, aponeurotic, mechanical, or traumatic in origin
Ptosis
- extremely rare, progressive genetic disorder
- causes children to age rapidly, starting in their first two years of life
- generally appear healthy at birth
Progeria
- genetic condition affecting a protein in the body called the fibroblast growth factor receptor
- protein begins to function abnormally, slowing down the growth of bone in the cartilage of the growth plate.
Achondroplasia
- condition in which a baby is born with one or more extra fingers
- common condition that often runs in families
- extra fingers are usually small and abnormally developed
Polydactyly
- caused by reduced or absent synthesis of the beta chains of hemoglobin
- manifests during 2nd year
- causes severe anemia, poor growth, skeletal abnormalities
- requires life-long blood transfusion
β-Thallasemia
where is the Thallasemia word from
Greek
thalassa (sea)
haemia (blood)
β-Thallasemia is caused by what
reduced or absent synthesis of beta chains of hemoglobin
when does β-Thallasemia progress
2nd year
what does β-Thallasemia cause
- severe anemia
- poor growth
- skeletal abnormalities
β-Thallasemia carrier without ilness, but less hemoglobin (slight anemia)
with one mutation less hemoglobin
β-Thallasemia major patient with severe anemia
with two mutations no β-globin
β-Thallasemia physical manifestations
- small head
- low nasal bridge
- epicanthal folds
- short nose
- flat midface
- smooth philtrum
- thin upper lip
- underdeveloped jaw
β-Thallasemia is a stabilizing selection against __
malaria
β-Thllasemia superiority
heterozygote superiority
two copies of an abnormal gene must be present in order for the disease or trait to develop
Autosomal recessive
β-Thllasemia highest prevalence
- Greeks (10%)
- Fil in Canada (4%)
- Taiwan (0.9%)
happens because they have less melanin than usual in their body
albinism
