Module 4, Section 2

genetic similarity, limited diversity, rapid population growth, and vulnerability to environmental change

what are the characteristics/consequences of asexual reproduction?

sexual reproduction

genetic material from two parents is combined to create a unique offspring with a new combination of genes

crossing-over, random fertilization, segregation, and independent assortment

what are some mechanisms that cause genetic diversity in sexual reproduction?

crossing over

during meiosis, homologous chromosomes can exchange segments of genetic material; results in a new combination of alleles on each chromosome

random fertilization

when gametes come together during fertilization, the specific combination of genes from each parent is random

segregation

during meiosis, homologous chromosomes separate and end up in different gametes

independent assortment

when homologous chromosomes line up during meiosis, they can align in different ways, resulting in different combinations of alleles being passed on to the offspring

genetic diversity

what is the main different between asexual and sexual reproduction?

adaptability

what does genetic diversity promote?

double helix composed of nucleotides

what is the structure of DNA?

storing genetic information and providing instructions for building and maintaining an organism

what is the function of DNA?

messenger, transfer, and ribosomal

what are the types of RNA?

protein synthesis

what is the role of RNA?

genes

specific sequences of DNA that code for proteins or RNA molecules; determine traits such as eye color, hair color, and height

sex-linked inheritance

the inheritance of genes located on the sex chromosomes and the different patterns of inheritance that result from their location

X

does the X or Y chromosome carry more information?

X-linked

is x-linked or y-linked inheritance more common?

hemophilia, color blindness, and Duchenne muscular dystrophy

what are some examples of x-linked disorders?

father to son

how is y-linked inheritance passed?

law of segregation

states that during the formation of gametes, the two alleles for a trait separate from each other so that each gamete carries only one allele

law of independant insortment

the distribution of one pair of homologous chromosomes into gametes during meiosis is independent of the distribution of other homologous chromosome pairs; alleles segregate into gametes randomly regardless of how other alleles are separating

gene linkage

the tendency of genes to be inherited together because they are located on the same chromosome; closer they are, more likely to be inherited together

recombination analysis

method used to study gene linkage and map the location of genes on a chromosome

phenotypes

physical traits that you can see

punnett squares

a tool used to predict probabilities regarding cross breeding

pedigree

display graphic that allows geneticists to track traits trough generation

circles

how are female represented on a pedigree?

squares

how are males represented on a pedigree?

presence of a trait

what do filled in shapes on a pedigree represent?

non-mendelian inheritance

traits that do not follow simple mendelian inheritance patterns

multiple allele

the existence of more than two possible alleles for a gene in a population; ABO blood group system

codominance

both alleles at a gene locus are expressed equally in the heterozygous individual, resulting in a phenotype where both alleles are expressed

incomplete dominance

heterozygous individual expresses and intermediate phenotype that is a blend of the two homozygous phenotypes

polygenic inheritance

the inheritance of a trait that is controlled by multiple genes, each with a small additive effect; the effect of one gene on a phenotype depends on the presence or absence of another gene

epistasis

expression of one gene is influenced by the presence of one or more other genes

pleiotropy

a single gene can have multiple effects on an organism’s phenotype

mutations

sudden and random changes in the DNA

somatic mutatinos

mutations occurring in body cells and are not passed on to offspring

gametes

mutations in _______ are passed along to offspring

spontaneous mutations, viral infections, mutagens, recombination, replication errors, transposons, and transcription errors

what are some caused of mutations?

mutagens

agents such as radiation or a chemical that causes a change in DNA

transposons

DNA sequences that can move around within the genome, causing insertions, deletions, or rearrangements of genetic material

point mutation

single nucleotide is changed to another

duplication mutation

genes are duplicated on a chromosome

inversion mutation

gene sections are reversed on a chromosome

translocation mutation

piece of chromosome breaks off and attaches to another chromosome

frameshift mutation

a nucleotide is either added or removed causing the entire codon sequence to change

silent mutations

mutations that do not change the amino acid sequence of the protein and therefore do not have an effect on its function

missense mutations

different amino acid being incorporated into the protein, which can affect its function

nonsense mutation

premature stop codon being incorporated into the protein, leading to a truncated and usually non-functional protein

repeat expansions

expansions of a repetitive DNA sequence, which can lead to genetic diseases such as Huntington’s and fragile X

no

are mutations always negative?

sickle cell anemia and cystic fibrosis

what are diseases caused by point mutations?

Tay-Sachs

what is a disease caused by a frameshift mutation?

Cri-du-chat and CML

what are some diseases caused by changes in chromosome structure?

down syndrome and tuner syndrome

what are some diseases caused by changes in chromosome number?

germline mutations

mutations occurring in sperm and egg cells that can be passed onto offspring

activators/enhancers

transcription factors that turn on a gene

repressors

transcription factors that interfere with the binding of activators so they prevent transcription and turn a gene off

gene regulation

the process of controlling gene expression, ensuring that genes are turned off or on at the right time and in the right place

transcriptional regulation

Controlling the rate at which genes are transcribed into mRNA.

post-transcriptional regulation

Modifying mRNA molecules after transcription, affects their stability and translation efficiency

translational regulation

Controlling the rate at which mRNA is translated into proteins

post-translational regulation

Modifying proteins after translation, affects their function and stability

epigenetics

the changes in gene expression that do not involve alterations to the DNA sequence itself but rather modifications to the chromatin structure or the addition of chemical marks to the DNA or histone protein that affect gene expression

DNA methylation, histone modifications, and non-coding RNA molecules

what are some of the common types of epigenetic modifications?

DNA methylation

involves the addition of a methyl group to cytosine residues in DNA, which can affect gene expression by blocking access of transcription factors to the DNA sequence

histone modifications

involve the addition or removal of chemical marks on histone proteins, which can alter the chromatin structure and affect gene expression

diet, chemical exposure, temperature, and light

what are some external environmental factors that can influence gene expression?

gel electrophoresis

a lab technique that separates DNA, RNA, or proteins by size and charge using an electric field and a gel matrix with pores

smaller molecules travel further

how are cell size and distance related in gel electrophoresis?

microscopy

the science of using microscopes to view and study objects that are too small to be seen with the naked eye

light microscopes

microscopes that use visible light to illuminate and magnify objects

electron microscopes

microscopes that use beams of electrons instead of light to create an image

scanning probe microscopes

microscopes that use a physical probe to scan the surface of an object and create an image with atomic-scale resolution

spectrophotometry

a scientific technique that involves the measurement of the absorption or transmission of light by a substance in a solution or a gas; used to determine the concentration of a substance in a solution, as well as to identify and quantify the presence of specific compounds in a sample

Beer-Lambert law

absorbance of a substance is directly proportional to its concentration, the path length of the light through the sample, and the extinction coefficient of the substance at the wavelength

polymerase chain reaction (PCR)

lab technique used for amplifying DNA; used in various fields including forensics, genetic engineering, medical diagnostics, and research

genome sequencing

the process of determining the complete DNA sequence of an organism’s genome; whole genome or targeted

gene therapy

a medical technique that involved the introduction or alteration of genetic material within a person’s cells to treat or prevent disease; goal is to correct or replace a defective gene

somatic gene therapy

involves the transfer of genetic material into the cells of an individual’s body with the goal of treating a specific disease or condition

germline gene therapy

involves altering the genetic material in eggs or sperm, which can be passed onto future generations

protein sequence analysis

involves determining the amino acid sequence of a protein and studying its structure, function, and evolution

bioinformatics analysis

involves using computer algorithms and software tools to analyze the protein sequence data and infer the protein’s structure and function

genetically engineered cells

involved modifying the DNA of cells or organisms, creating genetically engineered cells and transgenic organisms, with applications ranging from protein production to studying gene function and improving crops

chromosome analysis

the process of examining the number, structure, and organization of chromosomes in cells