- Chromosomes common in both genders - One from each parent

- One round of DNA replication - Two rounds of nuclear division

(6) Principles of Genetic Inheritance Flashcards by Jaime Weber

Define: Gene

Segments of DNA in a chromosome

How well did you know this?

Not at all

Perfectly

Define: Chromatid

one of two identical copies of chromosome

How well did you know this?

Not at all

Perfectly

Define: Centromere

Connects identical sister chromatids

How well did you know this?

Not at all

Perfectly

Define: Telomere

Region at end of chromosome for stability

How well did you know this?

Not at all

Perfectly

Human somatic cells are ________ cells

diploid

How well did you know this?

Not at all

Perfectly

Homologous chromosomes refer to _________

pairs of chromosomes

How well did you know this?

Not at all

Perfectly

Aa: what does the upper case and lower case letter represent?

A: wildtype

a: mutant

How well did you know this?

Not at all

Perfectly

Describe AUTOSOMES

Chromosomes common in both genders

- One from each parent

How well did you know this?

Not at all

Perfectly

Banding and nomenclature:

What does the small arm represent?

How well did you know this?

Not at all

Perfectly

Banding and nomenclature:

What does the long arm represent?

How well did you know this?

Not at all

Perfectly

Entire set of a pt. chromosmes represents their _____

karyotype

How well did you know this?

Not at all

Perfectly

How many chromosomes in pt’s diploid cells

How well did you know this?

Not at all

Perfectly

What is LYONIZATION?

X-activation

*The choice of which X chromosome to be inactivated is random

How well did you know this?

Not at all

Perfectly

What is MOSAICISM?

Condition in which cells from a pt. have different genotypes & karyotypes

How well did you know this?

Not at all

Perfectly

What are examples of conditions that result from mosaicism?

Downs syndrome
Klinefelter syndrome
Turner syndrome

How well did you know this?

Not at all

Perfectly

What is Down’s syndrome caused by genetically?

Mosaicism:

46XX
47XX
Trisomy 21

How well did you know this?

Not at all

Perfectly

What is Klinefelter syndrome caused by genetically?

Mosaicism:

46XY
47XXY

How well did you know this?

Not at all

Perfectly

What is Turner syndrome caused by genetically?

Mosaicism:

46XX
45XO

How well did you know this?

Not at all

Perfectly

Cell Cycle: Mitosis

What occurs during INTERPHASE?

Chromosome duplication

How well did you know this?

Not at all

Perfectly

Cell Cycle: Mitosis

Unique about stem cells?

Undergo mitosis but divide asymmetrically, resulting in one stem cell and one daughter cell

How well did you know this?

Not at all

Perfectly

Meiosis:

Goal?

Reduce the total number of chromosomes by half, producing four gametes (haploid)

How well did you know this?

Not at all

Perfectly

Meiosis consists of:

One round of DNA replication

- Two rounds of nuclear division

How well did you know this?

Not at all

Perfectly

Meiotic errors:

Euploid=

Cells with a normal number of chromosomes

How well did you know this?

Not at all

Perfectly

Meiotic errors:

Polyploidy=

presence of a complete set of EXTRA chromosomes in cells

*often seen in plants

How well did you know this?

Not at all

Perfectly

Meiotic errors: Aneuploidy=

Cells with a missing or additional individual chromsomes

TURNER SYNDROME: What is the karyotype? Sx?

45, XO Karyotype - Short stature - Ovarian hypofunction - Many do not undergo puberty - Most infertile - 30% webbed neck - CV defects - Normal intelligence

KLINEFELTER SYNDROME: Karyotype? Sx?

47, XXY - Some w/ limited/no sxs - Primary hypogonadism - Gynecomastia - Tall - Infertility - Variability in X numbers can increase symptoms

Trisomy 13, 18, 21 Identify each disorder based on the trisomy:

13: PATAU SYNDROME 18: EDWARDS SYNDROME 21: DOWNS SYNDROME

Genomic Imprinting: What is it?

-Gene silencing via methylation of 5' region of gene

Genomic Imprinting: Describe

- Epigenetic imprints remain throughout the lifespan of the individual in SOMATIC cells - In germ cells, epigenetic imprints are reset at each generation - During meiosis, imprints are erased and new ones are set

What are Prader-Willi/Angelman Syndromes defined by?

Deletion of a region of chromosome 15

How to Prader-Willi/Angelman syndromes differ?

*Difference occurs based on if deletion is on paternal or maternal chromosome

Describe the sx of Prader-Willie syndrome

- Short stature - Hypotonia - Small hands/feet - Obesity - Mild to moderate intellectual disability

Describe the sx of Angelman syndrome

- SEVERE intellectual disability - Seizures - Ataxic gait

What is Uniparental Disomy?

When two chromosomes are inherited from the same parent; they will have parent-specific imprinting

Mendelian Genetics: What demonstrated law of segregation in pea plants?

Tall or Dwarf

Mendelian Genetics: What demonstrated law of independent assortment?

Wrinkled/tall vs wrinkled/dwarf

Examples of genetic mechanisms of disease: Loss of function = Gain of function = Protein alteration =

Dystrophin (Duchenne MD) Oncogene (Cancer) Beta-globin (Sickle cell anemia)

# Define: Genotype

Individuals genetic makeup

# Define: Phenotype

What is actually observed

Individuals with distinct genotypes can have a ___________

Single phenotype *ex: Cystic fibrosis

What is PLEIOTROPHY?

Same genotype can have multiple phenotypes

Example of Autosomal Dominant Inheritance:

Postaxial polydactyly

How are AUTOSOMAL DOMINANT pedigrees identified?

- Affected offspring have one affected parent - Unaffected individuals do not transmit trait - Both males and females can transmit trait to both males and females - Trait is expected in every generation at 50%

AUTOSOMAL recessive inheritance

2 copies of gene is needed *example: tyrosinase negative albinism

How to identify a autosomal recessive pedigree?

- Affected individuals have normal parents | - Occurrence is more likely among individuals who share genes (cousin mating)

Example of X-linked recessive

Duchenne muscular dystrophy

Example of X-linked dominant

*super rareeeee Hypophosphatemia

The frequency of a gene manifests itself as _______

penetrance

Example of reduced penetrance?

Retinoblastoma

What is VARIABLE EXPRESSIVITY?

There is a range of phenotypes that vary b/w individuals with a specific genotype

Example of Variable Expressivity?

Neurofibromatosis

Example of Locus Heterogeneity?

Osteogenesis Imperfecta

Probability: What is the multiplication rule?

Probability of a given outcome in multiple trials is the product of the probabilities of each trial outcome *What is the probability of producing three girls? 1/2 x1/2 x1/2 =1/8

Probability: What is the addition rule?

Probability of either one outcome or another is the sum of the two probabilities *What is the probability of producing either three boys or three girls? 1/8 + 1/8 = 1/4

Mitochondrial Inheritance

INHERITED FROM MOM

Traits in which variations are thought to be caused by the combined effects of multiple genes are called _______

polygenic

When environmental factors cause variation in the trait, the term _________ is used

Multifactorial

What is an example of multifactorial inheritance?

Height

Prader-Willi syndrome: sx?

Short stature, hypotonia, small hands/feet, obesity, mild to moderate intellectual disability

Angelman syndrome: sx?

Severe intellectual disability, seizures, ataxic gait

How many genes can be imprinted by the father?

How many genes can be imprinted by the mother?

Mitochondrial Disorders What are the two?

Lebers (LHON) MELAS

Mitochondrial Disorders What is LHON?

Leber's hereditary optic neuropathy loss of vision

Mitochondrial Disorders MELAS?

Encephalopmyopathy, lactic acidosis, stroke-like episodes

What is an example of Multifactorial Inheritance?

Pyloric Stenosis Muscular hypertrophy b/w stomach and duodenum