Clinical Physiology Terms: Genetics, Genomics & Definitions

genes

what are the functional units of heredity

genetics

what is the study of genes

human genome

the complete set of DNA sequences from a gamete, person, population, or species

genomics

the study of the function and structure of the genome

epigenetics

the study of the marks (heritable changes) that alter gene expression

DNA methylation and histone modification (methylation/acetylation)

what 2 ways are most common to alter gene expression though marks left on the DNA without changing sequence

personalized medicine

a new approach for disease/treatment prevention that considers the variability of genes in an individual as a factor

deoxyribose

what is the name of the sugar within the backbone of DNA

phosphate

what is the name of the acid in the backbone of DNA

false, it is hydrophilic (likes water)

true or false: deoxyribose is hydrophobic

phosphate

phosphodiester bond

what does deoxyribose create a bond with. what is this bond called

A, C, T, G

they are located on the inside of the DNA double helix

what are the nucleotides in DNA, where are they located

Nucleic acid

the genome is the exact sequence of the ______________ ___________ bases in your DNA

a gene

a stretch of DNA that codes for protein or RNA

functional protein, coding RNA, non-coding RNA

what 3 things can a gene code for

phenotypic differences that may cause disease and the risk for disease

what can occur due to variation in a gene sequence

nucleosome

what is the term for DNA wrapped around a histone protein

without compaction it would be 2 meters long

why does DNA need to be compacted?

8

how many proteins make up the histone protein

the histone has a positive charge due to largely positive amino acid composition (lysine and arganine)

DNA is overall a negative charge, in order to wrap itself around a histone the charge needs to be neutralized, how is this achieved

the charges of DNA would repel itself, not allowing compaction

what would happen if the charge of DNA was not neutralized while compacting it?

formation of chromosome pairs

what is the highest level of DNA packing

23

how many chromosome pairs are in human cells

22 autosomal

1 sex

what is the ratio of autosomal vs sex chromosomes in human cells

2 chromatids (1 from each parent)

each chromosome is made up of....

each chromosome contains 2 copies of each gene

if there is 1 chromatid from each parent, what is the gene content in each chromosome?

genotype

defined as the base sequence of the genome

phenotype

the observed characteristics which is determined by the environment and epigenetic factors

chromatin

nucleosomes (histone + DNA packing) are tightly packed to make...

chromosomes

chromatin is the material that makes up...

heterochromatin

condensed chromatin that is transcriptionally inactive

nucleosomes are tightly condensed and transcriptional machinery (DNA to RNA) cannot access the DNA

why does heterochromatin decrease gene expression

euchromatin

open chromatin that is transcriptionally active

the nucleosomes are spaced further apart allowing access to the promotor on the DNA so transcription can occur

why does euchromatin increase gene expression

epigenetic marks

what determines the placement of heterochromatin and euchromatin in cells, ultimately determining gene expression?

heritable

epigenetic marks are __________ because of the nature of cells to divide

writers

readers

erasers

enzymes

epigenetic marks are added via __________, interpreted by _____________, and removed by ______________. All of these are _______________

histone modifications

____________ _____________ can increase/decrease gene expression though acetylation AND methylation

DNA would wrap tighter due to opposite charge attraction

what would the effect be of an additional positive charge added to a histone

decreased gene expression

histone de-acetylation

what effect would an additional positive charge on a histone would have what effect of gene expression? what would this modification be called

histone acetylation

removing the positive charge from a histone would increase gene expression due to decreased affinity of DNA to a neutral histone, what is this modification called

histone methylation can either increase OR decrease gene expression depending on where that methylation occurs

what is the effect of histone methylation

DNA methylation

which epigenetic mark on the DNA itself decreases gene expression

it blocks the binding of transcription factors

How does DNA methylation inhibit gene expression?

transcription factors bind to DNA and recruit RNA polymerase (transcription enzyme) to make RNA from the DNA

when there is no methyl group on DNA, how does gene expression occur

can either inhibit or enhance

long noncoding RNA has what effect on transcription?

it always inhibits it

microRNA has what effect on gene expression

in gene expression

DNA is identical throughout the body in ALL cells, how do these cells differ

it has roles in pre-RNA splicing in order to make actual RNA, translation, and RNA modification

what purpose does ncRNA serve?

epigenetic marks (they dictate which parts of DNA are accessible and which are not)

if differences in gene expression are what differentiates cells, what ultimately defines cell type

monogenic

diseases caused by one gene

polygenic

diseases caused by more than one gene

genomics projects, such as GWAS

what type of projects are in the process of figuring out what types of genetic variations are associated with disease? give an example

repetitive

according to the genome project, half of the human genome is made of what type of sequences

99.9%

what percent of sequences do humans share?

ELSI

what establishes and ensures privacy and confidentiality of genetic testing?

SNPs: single nucleotide polymorphisms

what is the name of the DNA sequential differences from individual to individual

it can alter its amino acid sequence and therefore the proteins function

What can the effect of an SNP be on a protein?

gametogenesis

sperm/ egg production, formation through meiosis

1, 4

In meiosis, ___ diploid parent cell ends in ____ non identical daughter cells

2

how many rounds of division are in meiosis

aneuploidy (abnormal number of chromosomes)

during meiosis, what occurs when there is mis-segregation of chromosomes

somatic division (mitosis)

what type of cell division is used in growth, differentiation, and tissue repair

1, 2

in mitosis, ___ diploid parent cell splits into ____ idential diploid daughter cells

over expression or under expression of proteins

what is the result of having too many or too few chromosomes?

single gene

loss of function (rarely a gain in function)

mutations at one or more sites in chromosomal DNA are called _______ gene defects, what is the result

multifactorial disorders

many genes are involved in these disorders and genes can increase/decrease the risk for these diseases

structural abnormalities

deletions, inversions, and translocations of the chromosome result in...

allele

variations of a gene

one trait

medelian traits are monogenic, meaning one gene=

autosomal dominant

this type of allele is present in every generation

autosomal recessive

this type of allele usually skips generations

x-linked

this type of allele only effects males and is passed down from the mother

complete dominance

when one allele completely masks the effect of the other when both alleles are present

incomplete dominance

when 2 alleles are present, an an intermediate phenotype is expressed

co dominance

when phenotypes of both parents are expressed

polygenic traits

traits determined by more than one gene

autosomal recessive

cystic fibrosis is an __________ __________ disease

SNPs

what does GWAS study to associate genetic variants with diseases?

case-control studies

what kind of study was used in the GWAS study of SNPs

correlation

causation

GWAS can establish __________________ not _________________!

association

observational studies can provide ________________ not causation

transcriptome

sequencing all the RNA molecules transcribed from a genome

epigenome

overall pattern of chromatin modifications possessed by each individual organism

microbiome

sequencing of fecal bacteria or fungi

ACTN3 and ACE

what genes are associated with athletic performance

577XX

this allele present on the ACTN3 gene is associated with decreased fast twitch muscle fibers and increased slow twitch muscle fibers. usually found in long distance runners and cyclists

577RR

this allele present on the ACTN3 gene is associated with increased fast twitch muscle fibers and decreased slow twitch muscle fibers. usually found in speed and strength athletes

it increases gene expression by promoting the de methylation of DNA (via erasers) and increasing acetylation of histones

what effect does exercise have on gene expression? how?

the promotor on the DNA

when DNA is demethylated, what is exposed and easily accessible to transcription factors to allow gene expression

chronic inflammatory disease

exercise also results in a decrease in ________________ ______________ ___________, an increase in muscle growth, and a decrease in muscle atrophy and mortality

exercise

what is the most potent medicine that preserves quality of life and expands healthspan

it may influence injury risk, rehabilitation response, or physical capacity

how does genetics pertain to physical therapy

- annual tear development

- degenerative disk disease and end plate herniations

Trp2 allel in the collagen 9 alpha-chain gene has been associated with the risk of what injury by 4x in 30-39 year olds, what else does it increase the risk of by 2.5x in 40-49 year olds

APOE e4

what gene variant has shown poorer response to rehabilitation after brain injury, this gene is also associated with alzeimers

postural sway, lumbar ROM, trunk flexibility, grip strength, gait speed, and 6 minute walk test

what functions have been shown to be influenced by genes through family studies (hint: there are 6)

they work to minimize the compensatory movements

what is the purpose of physical therapy for individuals with down syndrome