Principle Of Genetics Inheritance

Question 1

Genes

Answer 1

Segments of DNA in a chromosome

Question 2

Locus

Answer 2

The specific place of a gene

Question 3

Chromatin

Answer 3

One of two identical copies of a chromosome

Question 4

Centromere

Answer 4

Connects identical sister chromatids

Question 5

Telomere

Answer 5

Region at the end of the chromosome for stability

Question 6

Somatic cells

Answer 6

Diploid cells that are differentiated

Question 7

Homologous chromosomes

Answer 7

2 copies of each gene with the order of 4 loci being identical

Question 8

Auto some

Answer 8

Chromosomes common in both genders, and you get one from each parent

Question 9

Metacentric

Answer 9

Centromere is in the center of the chromosome

Question 10

Submetacentric

Answer 10

Just off the center. A short arm (P) and a long arm (Q)

Question 11

Acrocentric

Answer 11

Off center; very little information on the short arm so could be removed and the chromosome still functions normally

Question 12

17q11.2

Answer 12

17: chromosome number
Q: arm
1: region
1: band
2: subband

Question 13

Karyotype

Answer 13

entire set of patient’s chromosomes

Question 14

Lyonization

Answer 14

X-inactivation; chromosome that is inactivated is random

Question 15

Mosaicism

Answer 15

Condition in which cells from a patient have different genotypes in different areas of the body

Question 16

Stem cells

Answer 16

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

Question 17

Homologous recombination

Answer 17

Genes will switch locations so that the homologous chromosomes are not identical. Changes the sequence of alleles that are passed from generation to generation for genetic diversity

Question 18

Euploid

Answer 18

Cells with a normal number of chromosomes

Question 19

Polyploidy

Answer 19

Cells with missing or additional individual chromosomes

Question 20

Reciprocal NH chromosome exchange

Answer 20

An exchange of material between non homologous chromosomes

Question 21

Robertsonian exchange

Answer 21

Long arm of two acrocentric chromosomes will combine, leading to loss of the short arm

Question 22

Nondisjunction

Answer 22

Chromosome pairs do not split up, resulting in fertilization of zygotes with trisomy or monosomy.

Question 23

Prayer Willie syndrome

Answer 23

Paternal deletions of region of chromosome 15. Results in short stature, hypotonia, small hands/feet, obesity, and mild to moderate mental disability

Question 24

Angel man syndrome

Answer 24

Maternal deletion of region of chromosome 15. Results in severe intellectual disability, seizures, and ataxic gait.

Question 25

Klinefelter Syndrome

Answer 25

47,XXY Varying levels of symptoms depending on # of excess X. Varying degrees of cognitive/social difficulties. Hypogonadism, small testes, tall stature, infertility, and can be mosaic

Question 26

Trisomy 13, 18, 21

Answer 26

47, XX +21: Down syndrome. Increased risk w/ maternal age 47, XX+13: Patau syndrome. Severe developmental abnormalities and often results in perinatal death w/in 1 week 47, XX+ 18: Edwards syndrome. Leads to abnormal development and perinatal death w/in 1 year

Question 27

Proband (propositus)

Answer 27

First person diagnosed in a pedigree

Question 28

Penetrance

Answer 28

Frequency a gene is expressed. Can be 100% or less. In retinoblastoma, 90% of those with the gene express the phenotype so that is 90% penetrance

Question 29

Variable expressively

Answer 29

A range of phenotypes will vary between individuals with a specific genotype

Question 30

Locus heterogeneity

Answer 30

A single disorder, trait, or pattern of traits caused by mutations in genes at different chromosomal loci

Question 31

Probability multiplication rule

Answer 31

Probability of a given outcome in multiple trials is the product of the probabilities of each trial outcome Probability of three girls: 1/2+1/2+1/2=1/8

Question 32

Probability addition rule

Answer 32

Probability of either one outcome or the other is the sum of two probabilities Probability of three girls or three boys: 1/8 + 1/8 = 1/4

Question 33

Hardy Weinberg Principles

Answer 33

Shows relationship between gene frequencies and genotype frequencies. Know frequency of A (p) and deduce a (q) to be 0.7 and 0.3 respectively. Determine population frequency of each genotype AA, Aa, and aa AA: p^2=0.49 Aa: q^2=0.09 Aa: 2pq = 2(0.21)=0.42

Question 34

Consanguineous mating

Answer 34

More likely to produce offspring affected by rare recessive disorders.

Question 35

Leber’s hereditary optic neuropathy

Answer 35

Mitochondrial disorder. Causes degeneration of retinal ganglion cells and an acute or subacute loss of central vision —> typically in early teens or 20’s

Question 36

Mitochondrial encephalomyopathy, lactic acidosis, and stoke like episodes (MELAS)

Answer 36

Mitochondrial disorder. Affects many body systems, but mainly the brain, nervous system, and muscles. Stoke and dementia and lactic acidosis.

Question 37

Multifactorial inheritance

Answer 37

Environmental factors and genetics cause variation in the trait —> multifactorial