UNIT 2.1. Mendelian Genetics Flashcards
Branch of biology that deals with heredity and variation of organisms
Genetics
Carry the hereditary information
Chromosomes
The hereditary information
Genes
Contain DNA that codes for the same genes
Homologous chromosomes
T/F: Homologous chromosomes look alike and have the same genetic material
F (they look alike but are not the same)
T/F: Sister chromatids are exact replicas but homologous chromosomes are not
T
A unit of heredity
Gene
A section of DNA sequence encoding a single protein
Gene
The entire set of genes in an organism
Genome
Two genes that occupy the same position on homologous chromosomes and that cover the same trait
Alleles
A fixed location on a strand of DNA where a gene or one of its alleles is located
Locus
The genetic makeup of an organism
Genotype
The physical appearance of an organism
Phenotype
Genotype + environment
Phenotype
Having identical genes for a particular characteristic
Homozygous
Having two different genes for a particular characteristic
Heterozygous
A trait in which a gene is carried on a sex chromosome
Sex-linked trait
Traits controlled by genes on one of 22 pairs of autosomes
Autosomal trait
The allele of a gene that masks or suppresses the expression of an alternate allele
Dominant
The trait appears in the heterozygous condition
Dominant
An allele that is masked by dominant allele
Recessive
An allele that does not appear in the heterozygous condition
Recessive
An allele that only appears for homozygous
Recessive
A genetic cross involving a single pair of genes
Monohybrid cross
A genetic cross where parents differ by a single trait
Monohybrid cross
A genetic cross used for the Law of Segregation
Monohybrid cross
A genetic cross between two different genes that differ in two observed traits
Dihybrid cross
A genetic cross used for independent assortment
Dihybrid cross
P means ___
Parental generation
F1 means ___
First filial generation
F2 means ___
Second filial generation
A phenotype that is the most common expression of a particular allele combination in a population
Wild type
T/F: The wild type is only dominant
F (may be recessive or dominant)
A variant of a gene’s expression that arises when the gene undergoes a change
Mutant phenotype
Known as an illness that typically causes uncontrollable movements and changes in behavior and thinking
Huntington disease (HD)
The first distinction of single-gene diseases
How the px. is related to an affected relative
The second distinction of single-gene diseases
Tests can sometimes predict the risk of developing symptoms
T/F: all cells harbor the mutation if the person has inherited it
T
The third distinction of single-gene diseases
They may be much more common in some populations than others
T/F: Genes are selective of the type of people or certain populations
F (mutations stay in certain populations because we tend to have children with people similar to ourselves)
Many single-gene diseases affect fewer than 1 in ___ individuals
10 000
Consisting of sick children and their parents can reveal whether the child inherited two disease-causing mutations from carrier parents, or whether a dominant mutation arose anew
Tests of “trios”
A term where dominant mutation arose anew
“de novo”
Traits of two parents “blend” together and inherited by the offspring
Blending Theory of Inheritance
Seven traits Mendel looked at for his pea plant
- Round/Wrinkled
- Yellow/Green
- Purple/White petals
- Green/Yellow unripe pods
- Inflated/pinched ripe pods
- Axial/terminal flowers
- Long/short stems
Particulate Theory of Inheritance is also known as the ___
Gene idea
Involves the passing of discrete units of inheritance, or genes, from parents to offspring
Inheritance
The Particulate Theory of Inheritance is ___’s theory
Mendel
The theory where genes are present within chromosomes inside the cell
Chromosome Theory of Inheritance
In the Chromosome Theory of Inheritance, genes and chromosomes are in ____ in ____ cells
pair
diploid
Who proposed the Chromosome Theory of Inheritance?
Walter Sutton
Who proved the Chromosome Theory of Inheritance
Thomas Morgan
Insect used to prove the Chromosome Theory of Inheritance
Fruit fly
Enumerate the three principles of pattern of inheritance
- Principle of Dominance
- Principle of Segregation
- Principle of Independent Assortment
Identify the principle of pattern of inheritance: one allele masks another, one allele was dominant over the other in the F1 generation
Principle of Dominance
Identify the principle of pattern of inheritance: when gametes are formed, the pairs of hereditary factors (genes) become separated, so that each sex cell (egg/sperm) receives only one kind of gene
Principle of Seggregation
Identify the principle of pattern of inheritance: genes located on different chromosomes will be inherited independently of each other
Principle of Independent Assortment
T/F: true breeding always produce the same phenotype
T
“Gain of function”
Dominance
Action of an abnormal protein that interferes with the function of the normal protein
Dominance
A disease where the dominant mutant allele encodes an abnormally long protein that prevents the normal protein from functioning certain brain cells
Huntington disease
A single gene on chromosome ___, ___, confers the eye color by controlling melanin synthesis
15
OCA2
The gene missing which results in albinism
chromosome 15
OCA2
A recessive allele of ___ abolishes over OCA2 and results to blue eyes
HERC2
T/F: a person can inherit only one copy of the recessive allele HERC2 to have blue eyes
F (should inherit two copies)
T/F: in sickle cell disease, carriers can still develop a life-threatening breakdown of muscle if exposed to environmental heat
T
An individual with two different recessive alleles for the same gene is termed a ___
Compound heterozygote
T/F: most genes have two alleles and two variations of the associated traits
F (more than two)
___ variant is when a child has a recessive allele from each parent with the variant located at a different position within the same gene
Compound heterozygous (CH)
Type of nucleotide inheritance determination for 10X genomics or fosmid pool-based strategy
Laboratory-based
Type of nucleotide inheritance determination for SHAPEIT2, Beagle, Eagle2, HapCUT2
Computer-based
CH variants are understudies in ___ disease and may contribute to ___
pediatric
early disease onset
First genetic disorder for which mass post-natal genetic screening was available
Phenylketonuria
Phenylketonuria is caused by ___
Compound heterozygosity
A disease which may present in juvenile or adult onset which causes classic infantile disease
Tay-Sachs disease
A disease where an individual with one allele for hemoglobin S and one allele for hemoglobin C would still develop the disease despite being heterozygous
Sickle cell anemia
Arises from “loss of function”
Recessive
Inborn error of metabolism happens in ___ (dominant or recessive)
Recessive
____ (dominant or recessive) diseases tend to be more severe, and produce symptoms earlier, than dominant diseases
Recessive
Means “shared blood”
Consanguinity
Alleles inherited from shared ancestors are said to be “___”
Identical by descent
Identify is autosomal dominant or autosomal recessive: males and females affected, with equal frequency
Both
Identify is autosomal dominant or autosomal recessive: successive generations affected until no one inherits the mutation
Autosomal Dominant
Identify is autosomal dominant or autosomal recessive: affected individual has an affected parent, unless he or she has a de novo mutation
Autosomal Dominant
Identify is autosomal dominant or autosomal recessive: can skip generations
Autosomal Recessive
Identify is autosomal dominant or autosomal recessive: affected individual has parents who are affected or are carriers (heterozygotes)
Autosomal Recessive
Mendel’s 1st Law is the Law of ___
Segregation
Reflects the actions of chromosomes and the genes they carry during meiosis
Law of Segregation
The law of segregation uses ___ cross
Monohybrid
Mendel’s 2nd Law is the Law of ___
Independent Assortment
States that for two genes on different chromosomes, the inheritance of one gene does not influence the chance of inheriting the other gene
Law of Independent Assortment
In independent assortment, the two genes are said to “___” because they are packaged into gametes at random
Independently assort
The law of independent assortment uses ___ cross
Dihybrid
A lethal genetic disease affecting Caucasians
Cystic Fibrosis
Cystic fibrosis is caused by mutant recessive gene carried by 1 in ___ people of European descent
20
1 in ___ Caucasian couples will be both carriers of cystic fibrosis - 1 in ___ children will have it
400
4
A fatal genetic disorder that causes the progressive breakdown of nerve cells in the brain
Huntington Disease
Known as the quintessential family disease because every child of a parent with it has a 50/50 chance of inheriting the faulty gene
Huntington Disease
Allele for Huntington’s disease is ___ (dominant or recessive)
Dominant
Mating that involve parents that differ in two independent traits
Dihybrid cross
When you have an individual with an unknown genotype, you do a ___
Test cross
Cross with a homozygous recessive individual
Test cross
