Chapter 1 Human Genetics

Genetics

the study of traits and conditions encoded in DNA

DNA

Stores genetic information

Heredity

the transmission of traits and biological info between generations

Genetic Genealogy

how people are related

Genes

units of heredity, passed from one generation to
the next.

Genome

complete set of genetic information

Exome

part of genome that encodes proteins

Genomics

compares and analyzes the functions of genomes.

Bioethics

addresses issues and controversies that arise in applying medical technology and using genetic information

Components of DNA

phosphate, sugar, base

Bases of DNA

A,T,C,G

DNA Replication

a new double helix is formed from the old one
using free DNA bases.

DNA Transcription

copies the DNA information into RNA through the process called Gene Expression

DNA Translation

uses the information in RNA to assemble amino acids into proteins.

Mutation

change in gene

Alleles

variants of genes

Heritable mutation

in sperm and eggs

Chromosome

contains DNA and Protein

Stem Cells

divide to yield other stem cells and cells that
differentiate.

Somatic cell

any cell in the body, 2 genome copies ( diploid)

Autosome

22 pairs

Karyotypes

display the chromosome pairs from largest to smallest

Traits

Any observable characteristic

Mendelian Trait

trait mostly controlled by one gene

Complex trait

trait influenced by many genes and the environment

Genotype

underlying DNA instructions (alleles present)

Phenotypes

visible trait, biochemical change, or effect on health

Dominant

exerting an effect in a single copy

Recessive

requiring two copies for expression

Pedigrees

Family tree diagram showing who has a traits

Gene Pool

collection of alleles

DNA profiling

comparing DNA sequences to identify people or relationships

Differentiation

process by which cells become specialised

Biobanks

Place where many people’s samples and genetic data are stored for research.

Biogenomics

Study and comparison of whole genomes.

Precision medicine

Tailoring treatment to a person’s genes

Pharmacogenetics

Using genes to predict how someone will respond to a drug

Genetic modification

Changing genes in ways that don’t happen naturally.

Recombinant DNA

DNA made by combining genes from different species

Genome editing

can replace, remove, or add specific genes into the cells of any organism.

Exome sequencing

determines the order of the DNA bases

Metagenomics

involves sequencing all of the DNA in a habitat

Germ cell

reproductive, 1 genome copy( haploid)

Ribosomes

build proteins

Nucleus

holds DNA (genetic materi

Nuclear pores

allows movement of bio chemicals

Nuclear lima

provides support and holds nuclear pores in place

Nucleolus

produces ribosomes

Lysosomes

act as the cells waste disposal systems

Rough ER

synthesises proteins (have ribosomes on the surface)

Smooth ER

synthesises lipids

Golgi apparatus

packages and labels proteins and sugars

Endoscopes

vesicles derived from the plasma membrane that transport materials to lysosomes.

Peroxisomes

breakdown fatty acids and toxic substances

Vesicles

sacs used for transport

Biological membrane

transport of nutrients and waste, cell integrity

Signal transduction

detects signals from outside the cell and transmit them inwards

Cellular adhesion

Plasma membrane helps cells attach to other cells

Apoptosis

Cell death

Interphase

Chromosomes are uncondensed

Mitosis Cytokinesis

microfilament band contracts, seperating 2 cells

Single Gene Disease

caused by mutations in a single gene (monogenic)

True Breeding

offspring have the same trait as parent

Hybrids

plants that inherit a different gene variant (allele) from each parent.

Monohybrid

follows one trait

Dominant

the observed trait

Recessive

the masked trait

Homozygous

carry same alleles TT or tt

Heterozygous

carry different alleles Tt

Wild Type

Most common phenotype

Mutant phenotype

Variant of a gene’s expression that arises when the gene undergoes mutation

Law of segregation

allele pairs separate during the formation of gametes

OCA2

Help control melanin production in the iris

HERC2

controls expression of the OCA2 gene

Autosomal inheritance

can be dominant or recessive

Autosomal Dominant

equal frequencies and traits appear in every generations

Autosomal Recessive

equal frequencies and can skip generations

Recessive traits

loss of functions and proteins are missing

Dominant traits

arise from gain of function

dihybrid

heterozygous (RrYy)

Probability

likelihood that an event will occur

Lethal Alleles

genotype causes death before reproduction

Multiple Alleles

two alleles for each autosomal gene

Compound heterozygote

An individual with two different mutant recessive alleles for same gene

Codominance

both alleles are fully expressed in the heterozygote

Epistasis

one gene masks or affects another’s phenotypes

Penetrance

All-or-none expression of a single gene

Expressivity

Severity or extent

Pleiotropy

where one gene controls several functions

Genetic Heterogeneity

Different genes can produce identical phenotypes

Phenocopy

Trait that appears inherited but is caused by the environment

mtDNA

Contains small circular DNA

Heteroplasmy

condition where the mtDNA sequence is not the same in all copies of the genome

Linkage

Genes that are close on the same chromosome