2 Mendelian and Mitochondrial Inheritance Flashcards Preview

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Flashcards in 2 Mendelian and Mitochondrial Inheritance Deck (34):
1

what is unit inheritance?

parental phenotypes do not blend

2

segregation?

only one copy of each pair of genes is passed on

3

achondroplasia:
-inheritance?
-symptoms
-

-dominant
-short arms, legs, large head
-intelligence and life span normal

4

what is a tell tale sign of daminant inheritance on a pedigree?

every generation effected

5

what is variable expressivity?

the disease or condition can present with different or varying phenotypes (Marfans)

6

Marfans:
-inheritance
-physiology
-mortality

-mendel dominant
-connective tissue disorder, bone overgrowth and join laxity
-ruptured aorta

7

what is incomplete penetrance?

not everyone with the mutation will produce the phenotype (BRCA, and many other cancer mutations)

8

when are new (de novo) mutations common?

-occur at hot spots in the genome
-more common when the father is older, his sperm will begin to acrew more mutations

9

cystic fibrosis:
-inheritance?
-systems effected?
-reproductive issues?
-

-recessive
-primarily lung and GI
-95% of males are infertile due to flagella not functioning (Cl channel required)

10

if only one generation is affected on the pedigree, what could this mean?

recessive inheritance

11

recessive traits have less variability than dominant traits T/F

True, and penetrance is usually complete

12

Sickle Cell Anemia:
-inheritance
-ethnic predis
-clinical manifestation

-autosomal recessive
-prominent in african americans
-pain crises, organ damage

13

hemophilia:
-inheritance
-deficiency in what protein
-where does bleeding occur
-

-X linked recessive
-def in factor 8 or 9 depending on type
-internally, in joints or muscles

14

are females or males more likely to be affected by x linked recessive disorders?

males

15

what transmission is not possible in x linked recessive disorders?

male to male

16

what is lyonization?

the inactivation of one x chromosome in female cells
-this could be random (50/50) or skewed, leading to a phenotype in carriers of an x linked recessive condition

17

Duchenne muscular dystrophy:
-inheritance
-symptoms

-x linked recessive
-progressive degen of skeletal muscle, seemingly hypertrophic

18

would a female karyotype of 45, X leave this woman more susceptible to x linked recessive diseases?

yes

19

in what scenarios are females affected by X linked recessive traits?

-has a 45, X karyotype
-skewed X inactivation
-affected father and carrier mother (rare)
-the condition may also have a non-x-linked cause

20

incontinentia pigmenti:
-inheritance
-systems effected
-symptoms

-x linked dominant
-skin, hair, nails, eyes, and CNS. Skin lesions, alopecia, hypodontia, cognitive delays/disabilities

21

are males or females more likely to be affected by x linked dominant inheritance?

Females
-often lethal in males

22

where are the genes for ox phos found?

nuceleus, not the mitochondria

23

where do the mitochondrial genes come from

mother's oocyte, not father's sperm

24

what is MELAS?
-inheritance
-features

-mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes
-hearing loss, diabetes, seizures, intellectual disability

25

what is heteroplasmy?

a mixture of normal and abnormal mitochondria in the cytoplasm

26

what is homoplasmy?

all mtDNa is the same (abnormal or normal)

27

how are mitochondria segregated during mitosis?

randomly

28

what is the threshold effect with regard to mitochondrial disorders?

you need a certain number of malfunctioning mitochondria to express a phenotype. this phenotype may also vary depending on the % of abnormal mtDNA

29

how can the percentage of abnormal mtDNA change over time in different tissues?

-random genetic drift
-selective (replicative) advantage

30

how does age affect mitochondria?

-decreases with age thought is that there is oxidative damage from ox phos or an increased mutation rate
-if you have a mitochondrial disease it gets worse with age
-mitochondria might have a large effect on age in general

31

what tissues are effected most by mitochondrial diseases?

-tissues that require a lot of energy
-brain and muscle

32

what might be necessary in order to diagnose mitochondrial disorders?

muscle biopsy

33

if a diagnosis is made prenatally, what is the difficulty with determining prognosis?

heteroplasmy

34

what is nuclear transfrer?

a nucleus is removed from an oocyte with healthy mitochondria and discarded and then the nucleus is removed from an oocyte with abnormal mitochondria and placed inside the oocyte with abnormal mitochondria