Genetics

Question 1

What three factors can cause disease?

Answer 1

Genetics, Multifactorial or Enviromental

Question 2

What is a Autosome?

Answer 2

Any chromosome, other than the sex chromosomes (X or Y), that occurs in pairs in diploid cells

Question 3

What is a recessive gene?

Answer 3

Phenotype manifest only in homozygotes

Question 4

What is an Allele?

Answer 4

One or more alternative forms of a gene at a given location (locus)

Question 5

What is homozygous?

Answer 5

Presence of identical alleles at a given locus

Question 6

What is heterozygous?

Answer 6

alleles at a locus are different

Question 7

What is allelic heterogeneity?

Answer 7

The situation where different mutations within the same gene result in the same clinical condition

Question 8

What is consanguinity?

Answer 8

Reproductive union between two relatives

Question 9

What is autozygosity?

Answer 9

Homozygosity by descent, i.e. inheritance of the same altered allele through two branches of the same family.

Question 10

What is penetrance?

Answer 10

The percentage of individuals with a specific genotype showing the expected phenotype

Question 11

What is expressivity?

Answer 11

Refers to the range of phenotypes expressed by a specific genotype

Question 12

What is anticipation?

Answer 12

Whereby genetic disorder affects successive generations earlier or more severely, usually due to expansion of unstable triplet repeat sequences

Question 13

What is Somatic Mosaicism?

Answer 13

Genetic fault present in only some tissues in body.

Question 14

What is Gonadal (germline) Mosaicism?

Answer 14

Genetic fault present in gonadal tissue

Question 15

What is Late-onset?

Answer 15

Condition not manifest at birth (congenital), classically adult-onset

Question 16

What is sex-limited?

Answer 16

Condition inherited in AD pattern that seems to affect one sex more than another

Question 17

What is predictive testing?

Answer 17

Testing for a condition in a pre-symptomatic individual to predict their chance of developing condition

Question 18

What is Lyonization?

Answer 18

Generally only one of two X chromosomes active in each female cell. Can be skewed (X inactivation)

Question 19

Where is mitochondrial DNA inherited from?

Answer 19

The Mother

Question 20

What is homoplasmy?

Answer 20

a eukaryotic cell whose copies of mitochondrial DNA are all identical (identically normal or have identical mutations)

Question 21

What is heteroplasmy?

Answer 21

there are multiple copies of mtDNA in each cell

Question 22

What is genotype?

Answer 22

genetic constitution of an individual

Question 23

What is phenotype?

Answer 23

appearance of an individual (physical, biochemical, physiological) which results from the interaction of the environment and the genotype

Question 24

What is polymorphism?

Answer 24

Frequent hereditary variations at a locus

Question 25

What is hemizygous?

Answer 25

only one allele refers to a locus on an X chromosome in a male

Question 26

What is Autosomal Dominance Inheritance?

Answer 26

Disease which is manifest in the heterozygous state

Question 27

What is Autosomal Recessive Inheritance?

Answer 27

Disease which is manifest in the homozygous state

Question 28

What is X-Linked Recessive Inheritance?

Answer 28

Caused by pathogenic variants in genes on the X chromosome

Question 29

What is Multifactorial conditions?

Answer 29

Diseases that are due to a combination of genetic and environmental factors