MIDTERM LEC 1: MENDELIAN GENETICS Flashcards
1
Q
___________ - inheritance of a trait or characteristic that is controlled by a SINGLE GENE aka_____________
A
SINGLE-GENE INHERITANCE; MENDELIAN INHERITANCE
2
Q
SINGLE-GENE TRAITS is also known as
A
MONOFACTORIAL TRAITS or MENDELIAN
3
Q
CHARACTERISTICS OF SINGLE-GENE TRAITS
A
- Relationship with the affected relative
- Tests can sometimes predict the risk of developing symptomes
- More common in some populations than others
- It may be fixable
4
Q
example of single-gene traits
A
widow’s peak, dimple, earlobes, albinism
5
Q
Definition of terms
- alternative form of gene
A
ALLELE
6
Q
Definition of terms
- allele that masks another, has an effect when present in just 1 copy (CAPITAL LETTER)
A
DOMINANT ALLELE
7
Q
Definition of terms
- masked, must be present on both chromosomes of a pair to be expressed (small letter)
A
RECESSIVE ALLELE
8
Q
Definition of terms
- 2 identical alleles (true - breeding)
A
HOMOZYGOUS
9
Q
Definition of terms
- 2 different alleles (non-true breeding/hybrid)
A
HETEROZYGOUS
10
Q
Definition of terms
- underlying instructions (alleles present)
A
GENOTYPE
11
Q
Definition of terms
- visible trait, outward expression of an allele combination
A
PHENOTYPE
12
Q
Definition of terms (what type of trait)
- 1 trait that masks another
A
DOMINANT TRAIT
13
Q
Definition of terms (dominant or recessive trait)
- masked trait
A
RECESSIVE TRAIT
14
Q
An organism’s appearance does not always reveal it’s alleles
TRUE or FALSE?
A
TRUE
15
Q
Definition of terms
- phenotype, most common expression of a particular allele combination in a population
Wild or mutant type
A
WILD TYPE
16
Q
Definition of terms
- phenotype, variant of a gene’s expression that arises when the gene undergoes CHANGE
A
MUTANT TYPE
17
Q
Example of mutant type in Humans
A
Albino
18
Q
Example of wild type in Humans
A
Caucasoid
Mongoloid
Negroid
19
Q
MENDELS EXPERIMENT
In ________, Mendel crossed and cataloged traits in 24,034 plants, through several generations. He term units of heredity as “ELEMENTEN”.
A. 1857-1863
B. 1866
C. 1901
A
1857-1863
20
Q
Mendel published “EXPERIMENT ON PLANT HYBRIDIZATION on” _______
A. 1857-1863
B. 1866
C. 1901
A
1866
21
Q
HUGO DE VRIES (Holland), CARL CORRENS (Germany , and ERICH VON TSCHERMAK (Austria) used Mendel’s theory making him know into the field
A. 1857-1863
B. 1866
C. 1901
A
1901
22
Q
Mendel term the unit of heredity as
A
ELEMENTEN
23
Q
The term ELEMENTEN was renamed by ________ as “genes” (Greek for “give birth to”)
A
WILLIAM BATESON (1909)
24
Q
Genes is Greek for
A
Give birth to
25
Why did Gregor Johann Mendel use pea plants in his experiment?
- EASY TO GROW
- DEVELOP QUICKLY
- HAVE MANY TRAITS THAT TAKE ONE OF TWO EASILY DISTINGUISHABLE FORMS
26
In analyzing genetic crosses _________ is the first generation
Parental Generation or P1
27
In analyzing genetic crosses
_____________________ is the second generation
First Filial Generation or F1
28
In analyzing genetic crosses
____________ is the next generation
Second Filial Generation or F2
29
Punnett square was named after ___________ who 1st devised this apporach
Reginald C. Punnett
30
A tool used to predict the possible genotypes & phenotypes of offspring of resulting from a cross between 2 individuals
- represents how genes in gametes join if they are on different chromosomes
PUNNETT SQUARE
31
Mendel's observation in his experiments:
- producing the same phenotype
- have the same trait as parent
Ex: A true - breeding purple plant crossed itself will always produce offspring that are purple as well
TRUE - BREEDING
32
Mendel's observation in his experiments:
- follows 1 trait & the self-crossed plants are HYBRIDS
- true-breeding plant with 2 forms of a single gene trait are crossed
MONOHYBRID CROSS
33
- hides one expression of a trait, which appears when hybrids are self-crossed
Punnett Square or Monohybrid Cross
Monohybrid Cross
34
In monohybrid cross, hybrids can hide one expression of a trait, which reappears when hybrids are self-crossed
How did this happen?
GAMETES DISTRIBUTE "ELEMENTEN".
Paired set of ELEMENTEN separates gametes form. When gametes join at fertilization, the ELEMENTEN combine anew.
35
Mendel's first law, distribution of alleles of a gene into separate gametes during meiosis
LAW OF SEGREGATION
36
Chromosomes of parent 1 and 2 replicate in _________
A. Anaphase
B. Metaphase
C. INTERPHASE
D. Monophase
INTERPHASE
37
In ______ alleles segregates into gametes
Meiosis or Mitosis
MEIOSIS
38
Used to determine the GENOTYPE of an individual showing a DOMINANT PHENOTYPE.
Ex: The pea plant is tall ( tall is dominant), is it heterozygous (Tt) or Homozygous (TT) ?
Punnett square or Monohybrid Cross or Test Cross
TEST CROSS (BACK CROSS)
39
- Pattern by which a GENETIC TRAIT/DISORDER IS PASSED FROM 1 GENERATION TO THE NEXT WITHIN A FAMILY
MODE OF INHERITANCE
40
MODE OF INHERITANCE
A way that a trait is passed depends on whether:
A. The gene that determines is an autosome or sex chromosomes and,
B. Whether the allele is recessive or dominant
41
MODE OF INHERITANCE includes
1. AUTOSOMAL DOMINANT INHERITANCE
2. AUTOSOMAL RECESSIVE INHERITANCE
3. SEX - INHERITANCE
a. Y - linked inheritance
b. X - linked dominant inheritance
c. X - linked recessive inheritance
42
- trait/disorder is caused by a DOMINANT ALLELE LOCATED ON 1 OF THE AUTOSOMAL CHROMOSOMES
- a single copy of the dominant allele will exhibit the trait/disorder
AUTOSOMAL DOMINANT INHERITANCE
43
Criteria in AUTOSOMAL DOMINANT INHERITANCE
1. Males and females can be affected. (Male-to-male transmission can occur
2. Males and females transmit the trait with equal frequency
3. Successive generations are affected
4. Transmission stops after a generation in which no one inherits the mutation
44
For many autosomal dominant traits/disorders, affected individuals are HETEROZYGOUS. The HOMOZYGOUS dominant phenotype is either lethal or very rare
True or false
True
45
- trait/disorder is caused by a RECESSIVE ALLELE located on 1 of the autosomal chromosomes
- 2 copies of the recessive allele (homozygous) to exhibit the trait or disorder
AUTOSOMAL RECESSIVE INHERITANCE
46
Criteria for AUTOSOMAL RECESSIVE INHERITANCE
1. Males and females can be affected
2. Affected females and males can transmit the gene, unless it causes death before reproductive age
3. The trait can skip generations
4. Parents of an affected individual are heterozygous or have the trait.
Ex: albinism
47
AUTOSOMAL RECESSIVE INHERITANCE
- affected individuals are HOMOZYGOUS RECESSIVE. Carriers are heterozygous and asymptomatic
Ex: Albino
True or false?
True
48
- Pattern of inheritance of genetic traits/disorders that
are located on the sex chromosomes
SEX - LINKED INHERITANCE
49
SEX - LINKED INHERITANCE
- Involves genes located on the Y CHROMOSOMES & traits/disorders are rare because it has few genes
- Passed from male-to-male(father-to-sons)
- No affected females
Y-LINKED INHERITANCE
50
EXAMPLE OF Y-LINKED INHERITANCE
- inability to conceive
A. MALE INFERTILITY
B. Y-LINKED CONGENITAL HYPOPLASIA
C. RETINITIS PIGMENTOSA 2 (RP2)
MALE INFERTILITY
51
EXAMPLE OF Y-LINKED INHERITANCE
- impaired development of the adrenal glands
A. MALE INFERTILITY
B. Y-LINKED CONGENITAL HYPOPLASIA
C. RETINITIS PIGMENTOSA 2 (RP2)
Y-LINKED CONGENITAL HYPOPLASIA
52
EXAMPLE OF Y-LINKED INHERITANCE
- progressive vision loss due to the degeneration of photoreceptor cells in the retina
A. MALE INFERTILITY
B. Y-LINKED CONGENITAL HYPOPLASIA
C. RETINITIS PIGMENTOSA 2 (RP2)
RETINITIS PIGMENTOSA 2 (RP2)
53
SEX - LINKED INHERITANCE
- Recessive allele is located on the X CHROMOSOME
- Always expressed in MALES (inherited from heterozygote/ homozygote mother)
- Expressed in females if the CAUSATIVE ALLELES IS PRESENT IN 2 COPIES (inherited from affected father & affected heterozygote mother)
- Females are usually CARRIERS (heterozygotes) & asymptomatic)
X-LINKED RECESSIVE INHERITANCE
54
EXAMPLE OF X-LINKED RECESSIVE DISORDERS
- rough, brown, scaly skin, an enzyme deficiency blocks removal of cholesterol from skin cells
A. ICHTHYOSIS
B. COLORBLINDNESS
C. HEMOPHILIA
ICHTHYOSIS
55
EXAMPLE OF X-LINKED RECESSIVE DISORDERS
- affects an individual's ability to perceive or distinguish certain colors
A. ICHTHYOSIS
B. COLORBLINDNESS
C. HEMOPHILIA
COLORBLINDNESS
56
EXAMPLE OF X-LINKED RECESSIVE DISORDERS
- blood - clotting disorder
A. ICHTHYOSIS
B. COLORBLINDNESS
C. HEMOPHILIA
HEMOPHILIA
57
SEX - LINKED INHERITANCE
- Dominant allele located on the X chromosome
- Expressed in FEMALES IN 1 COPY and they are more likely to be affected
- Much more severe effects in males
- Passed from MALE TO ALL DAUGHTERS, but to no sons
X-LINKED DOMINANT INHERITANCE
58
X-LINKED DOMINANT DISORDERS
- neurological and developmental disorder
A. RETT SYNDROME
B. INCONTINENTIA PIGMENTI
C. CONGENITAL HYPERTRICHOSIS
RETT SYNDROME
59
X-LINKED DOMINANT DISORDERS
- primarily affects the skin, hair, teeth, and nervous system
A. RETT SYNDROME
B. INCONTINENTIA PIGMENTI
C. CONGENITAL HYPERTRICHOSIS
INCONTINENTIA PIGMENTI
60
X-LINKED DOMINANT DISORDERS
- werewolf syndrome, characterized by excessive hair growth over the body
A. RETT SYNDROME
B. INCONTINENTIA PIGMENTI
C. CONGENITAL HYPERTRICHOSIS
CONGENITAL HYPERTRICHOSIS
61
INHERITANCE OF MORE THAN ONE GENE
Mendel's 2nd law: States that for 2 genes on different chromosomes, the inheritance of 1 gene does not influence the chance of inheriting the other gene
LAW OF INDEPENDENT ASSORTMENT
62
INHERITANCE OF MORE THAN ONE GENE
- 2 genes and traits are followed
A. MONOHYBRID CROSS
B. DIHYBRID CROSS
C. TEST CROSS
DIHYBRID CROSS
63
- Charts that display family relationship and depicts which relatives have specific phenotypes and sometimes, genotypes
- May also include molecular data, test results, and information on variants of multiple genes
PEDIGREES
64
PEDIGREE ANALYSIS
Skips a generation through carriers
Both males and females are affected
A. Pedigree for an autosomal recessive trait/disorder
B. Pedigree for an autosomal dominant trait/disorder
C. Pedigree for a Y-linked trait/disorder
D. Pedigree for a X-linked recessive trait/disorder
E. Pedigree for a X-linked dominant trait/disorder
Pedigree for an autosomal recessive trait/disorder
65
PEDIGREE ANALYSIS
Does not skip a generation
Both males and females are affected
A. Pedigree for an autosomal recessive trait/disorder
B. Pedigree for an autosomal dominant trait/disorder
C. Pedigree for a Y-linked trait/disorder
D. Pedigree for a X-linked recessive trait/disorder
E. Pedigree for a X-linked dominant trait/disorder
Pedigree for an autosomal dominant trait/disorder
66
PEDIGREE ANALYSIS
All males are affected
A. Pedigree for an autosomal recessive trait/disorder
B. Pedigree for an autosomal dominant trait/disorder
C. Pedigree for a Y-linked trait/disorder
D. Pedigree for a X-linked recessive trait/disorder
E. Pedigree for a X-linked dominant trait/disorder
Pedigree for a Y-linked trait/disorder
67
PEDIGREE ANALYSIS
Females are usually carriers (heterozygotes)
Always expressed in males
A. Pedigree for an autosomal recessive trait/disorder
B. Pedigree for an autosomal dominant trait/disorder
C. Pedigree for a Y-linked trait/disorder
D. Pedigree for a X-linked recessive trait/disorder
E. Pedigree for a X-linked dominant trait/disorder
Pedigree for a X-linked recessive trait/disorder
68
PEDIGREE ANALYSIS
Expressed both in males and females
Passed from male to all daughters, but to no sons
A. Pedigree for an autosomal recessive trait/disorder
B. Pedigree for an autosomal dominant trait/disorder
C. Pedigree for a Y-linked trait/disorder
D. Pedigree for a X-linked recessive trait/disorder
E. Pedigree for a X-linked dominant trait/disorder
Pedigree for a X-linked dominant trait/disorder
