Genetics The study of genes and the inheritance of traits This Powerpoint is hosted on Please visit for 100’s more free powerpoints

DNA Chromosomes are made of a chemical called DNA Chromosomes are made of a chemical called DNA DNA looks like a twisted ladder DNA looks like a twisted ladder Steps of the ladder are made of Adenine, guanine, thymine, cytosine, or A,G,T,C Steps of the ladder are made of Adenine, guanine, thymine, cytosine, or A,G,T,C The arrangement of a, g, t, c makes up an individual’s genetic code The arrangement of a, g, t, c makes up an individual’s genetic code

Characteristics These are features you exhibit physically These are features you exhibit physically ( your looks) ( your looks) Example: Eye color - green

Traits The different versions of a characteristic The different versions of a characteristic Example: blue, green, and brown eyes Example: blue, green, and brown eyes

Inheritance Occurs when traits are passed down from parent to child. Occurs when traits are passed down from parent to child.

Inherited traits traits are characteristics of an organism traits are characteristics of an organism Traits are passed from parents to their offspring are called inherited traits Traits are passed from parents to their offspring are called inherited traits 1 st person to study heredity: MENDEL 1 st person to study heredity: MENDEL genes control inherited traits genes control inherited traits different forms of the same gene are called alleles ex. brown, blonde, red hair different forms of the same gene are called alleles ex. brown, blonde, red hair

Genes Bits of information passed down from parent to child. Bits of information passed down from parent to child. Made of chemicals called DNA. Made of chemicals called DNA.

Fertilization Occurs when a sperm unites with an egg Occurs when a sperm unites with an egg

Type 2- sexual reproduction Type 2- sexual reproduction is where an organism is formed when 2 sex cells (egg/sperm) come together from 2 parents with genetic material from both. is where an organism is formed when 2 sex cells (egg/sperm) come together from 2 parents with genetic material from both.

Offspring Another name for the children of a male and female parent Another name for the children of a male and female parent

Genetics The study of genes and the inheritance of traits This Powerpoint is hosted on Please visit for 100’s more free powerpoints

Reproduction Sexual – 2 parents. Sperm fertilizes an egg to produce offspring Sexual – 2 parents. Sperm fertilizes an egg to produce offspring Asexual – 1 parent. Occurs when 1 organism copies itself to produce offspring Asexual – 1 parent. Occurs when 1 organism copies itself to produce offspring

Types of reproduction Type 1: asexual- a new organism is produced from one parent with identical genetic material Type 1: asexual- a new organism is produced from one parent with identical genetic material Budding- a small, exact copy of the adult grows from the body of the parent ex. hydra, Regeneration- when a whole new organism grows from broken pieces of the parent ex. starfish, sponges Regeneration- when a whole new organism grows from broken pieces of the parent ex. starfish, sponges Fission- an organism like bacteria divides into 2 identical organisms Fission- an organism like bacteria divides into 2 identical organisms

Traits Dominant trait – covers (hides) other traits (usually represented by a capital letter Ex: B=brown hair) Dominant trait – covers (hides) other traits (usually represented by a capital letter Ex: B=brown hair) Recessive trait – doesn’t show in the presence of dominant traits (usually represented by a lower case letter b =blonde hair]) Recessive trait – doesn’t show in the presence of dominant traits (usually represented by a lower case letter b =blonde hair])

alleles alleles each trait is controlled by at least 1 gene from each parent each trait is controlled by at least 1 gene from each parent a dominant allele (gene) always shows itself over a recessive allele (gene) a dominant allele (gene) always shows itself over a recessive allele (gene) Chromosomes contain genes Chromosomes contain genes

Homozygous/Heterozygous Homozygous – an organism whose genotype has two alleles that are the same – either dominant or recessive (Ex: BB or bb) Homozygous – an organism whose genotype has two alleles that are the same – either dominant or recessive (Ex: BB or bb) Heterozygous – an organism whose genotype has two different alleles – dominant AND recessive (Ex: Bb) Heterozygous – an organism whose genotype has two different alleles – dominant AND recessive (Ex: Bb)

traits Pure or homozygous-offspring has 2 like alleles for a trait Pure or homozygous-offspring has 2 like alleles for a trait Hybrid or heterozygous –offspring has 2 unlike alleles for a trait Hybrid or heterozygous –offspring has 2 unlike alleles for a trait

Genotype/Phenotype Genotype – genetic makeup of an organism (cannot see an organism’s genotype) Genotype – genetic makeup of an organism (cannot see an organism’s genotype) Phenotype – way an organism looks due to its genotype (its physical appearance) *remember Phenotype and Physical start with PH* Phenotype – way an organism looks due to its genotype (its physical appearance) *remember Phenotype and Physical start with PH* Genotype BB you would see brown hair Genotype BB you would see brown hair bb= blonde hair, Bb= brown hair bb= blonde hair, Bb= brown hair

Genotype A combination of alleles A combination of alleles Example: TT, Tt, or tt Example: TT, Tt, or tt

Phenotype They are the traits determined by reading the genotype. They are the traits determined by reading the genotype. Example : FF = black fur Example : FF = black fur Black fur is the phenotype or trait Black fur is the phenotype or trait

Look at your traits sheets

What’s your phenotype? B= brown eyesb= blue eyes B= brown eyesb= blue eyes T=tallt=short T=tallt=short F=frecklesf= no freckles F=frecklesf= no freckles C=curly hairc=not curly hair C=curly hairc=not curly hair H=hair on fingersh= no hair on fingers H=hair on fingersh= no hair on fingers D=dimples d= no dimples D=dimples d= no dimples R=roll tonguer= can’t roll tongue R=roll tonguer= can’t roll tongue W=widow’s peakw= no widow’s peak W=widow’s peakw= no widow’s peak A=attached ear lobe a= unattached ear lobe A=attached ear lobe a= unattached ear lobe

Punnett Square Uses mom and dad’s genotypes to determine the possible traits of their offspring. Uses mom and dad’s genotypes to determine the possible traits of their offspring. Each box represents 25% chance of that trait being inherited. Each box represents 25% chance of that trait being inherited.

Punnett Squares are tools used to predict possible gene combinations of offspring are tools used to predict possible gene combinations of offspring capital letters represent dominant traits ex. B capital letters represent dominant traits ex. B lowercase letters represent recessive ex. b lowercase letters represent recessive ex. b heterozygous- 2 unlike alleles for a trait (Bb) heterozygous- 2 unlike alleles for a trait (Bb) homozygous- 2 like alleles for a trait (bb) homozygous- 2 like alleles for a trait (bb) phenotype- way an organism looks as a result of its genotype phenotype- way an organism looks as a result of its genotype genotype- the actual traits inherited (Bb) genotype- the actual traits inherited (Bb)

Phenotypes – What you see physically! In what two genotypes will the dominant trait be seen? In what two genotypes will the dominant trait be seen? Capital letter, capital letter Capital letter, capital letter Capital letter, lower case letter Capital letter, lower case letter What is the genotype if the trait seen is recessive? What is the genotype if the trait seen is recessive? Lower case, lower case Lower case, lower case

Alleles T – is considered a dominant allele T – is considered a dominant allele t – is considered a recessive allele t – is considered a recessive allele TT – is dominant Tt – is dominant tt - is recessive

Copy the following key for genotypes: Freckles (F) Curly hair (H) Breathes fire (F) Purple flowers (P) with white as recessive Blue body (B) with green as recessive Write 3 possible genotypes for the above traits. Write 3 possible genotypes for the above traits.

FF; Ff; ff FF; Ff; ff FF – Freckles; Ff – freckles; ff – no freckles FF – Freckles; Ff – freckles; ff – no freckles HH; Hh; hh HH; Hh; hh HH – Curly hair; Hh – Curly hair; hh – straight hair HH – Curly hair; Hh – Curly hair; hh – straight hair FF; Ff; ff FF; Ff; ff FF – fire breathing; Ff – fire breathing; ff – no fire FF – fire breathing; Ff – fire breathing; ff – no fire PP; Pp; pp PP; Pp; pp PP – Purple Flower; Pp – Purple flower; pp – white flower PP – Purple Flower; Pp – Purple flower; pp – white flower BB; Bb; bb BB; Bb; bb BB – Blue body; Bb – Blue body; bb – green body BB – Blue body; Bb – Blue body; bb – green body What is the phenotype for each? What is the phenotype for each?

Key T=tallB=blackR=roundS=curly hair t= shortb=blonder=ovals=straight hair Give the genotype for the following: ____ a heterozygous tall person Tt ____ a blonde golden retriever bb ____ a homozygous oval shaped face rr ____ a homozygous curly hair poodle SS ____ a heterozygous round shaped face Rr ____ a purebred black fur lab puppy BB

R=round bodyH=hairT=tall R=round bodyH=hairT=tall r= square bodyh=baldt=short r= square bodyh=baldt=short Give the phenotype for each genotype, tell whether it is Heterozygous or Homozygous. Give the phenotype for each genotype, tell whether it is Heterozygous or Homozygous. RR___________ He or Ho? RR___________ He or Ho? Hh___________ He or Ho? Hh___________ He or Ho? Rr___________ He or Ho? Rr___________ He or Ho? Tt___________ He or Ho? Tt___________ He or Ho? rr ___________ He or Ho? rr ___________ He or Ho? HH __________ He or Ho? HH __________ He or Ho? tt ___________ He or Ho? tt ___________ He or Ho?

R=round bodyH=hairT=tall R=round bodyH=hairT=tall r= square bodyh=baldt=short r= square bodyh=baldt=short Give the genotype for the given phenotype: Give the genotype for the given phenotype: _______ bald headed _______ bald headed _______ heterozygous tall _______ heterozygous tall _______ heterozygous round body _______ heterozygous round body _______ heterozygous hair on head _______ heterozygous hair on head _______ square body _______ square body _______ round body _______ round body _______tall person _______tall person

….Practice Continued B = brown hair b = blonde hair John has heterozygous brown hair while his wife has blonde hair. If they had a child what percentage would have blonde hair? What percentage would be heterozygous?

Practice genotypes: Rr Rr genotypes: Rr Rr phenotypes: R= right handed phenotypes: R= right handed r= left handed r= left handed

Heterozygous Tall ____% Homozygous Tall ____% Short ____% T t T t T t

Polygenic inheritance A combination of many genes acts together to produce a trait A combination of many genes acts together to produce a trait eye color, height, hair eye color, height, hair skin color is controlled by 3-6 gene pairs skin color is controlled by 3-6 gene pairs At least 2 genes determine human eye color. That’s why so many shades of a single color are possible.

Incomplete Dominance Occurs when neither allele is dominant resulting in an almost blending of the two. Occurs when neither allele is dominant resulting in an almost blending of the two. Production of a phenotype that is intermediate between two homozygous parents. Production of a phenotype that is intermediate between two homozygous parents.

Incomplete dominance When neither allele is dominant over the other When neither allele is dominant over the other The phenotype produced is a blend of the two alleles The phenotype produced is a blend of the two alleles

C1C1 C1C1 C1C1 C1C1 C1C1 C1C1 CC C C CC Ex. Horses: Brown chestnut X White cremello Ex. Horses: Brown chestnut X White cremello

Ex: Red flower X White flower Ex: Red flower X White flower

Codominance Occurs when both alleles are dominant resulting in both traits appearing. Occurs when both alleles are dominant resulting in both traits appearing. Both alleles of a certain trait show up in the offspring’s phenotype Both alleles of a certain trait show up in the offspring’s phenotype Is different from incomplete dominance because it is not a blending of the 2 traits but both alleles appear independently of each other in the offspring Is different from incomplete dominance because it is not a blending of the 2 traits but both alleles appear independently of each other in the offspring

White chicken X Black chicken White chicken X Black chicken

Black & White X Black & White

Multiple alleles A trait controlled by more than 2 alleles & Produces more than 3 phenotypes for that trait A trait controlled by more than 2 alleles & Produces more than 3 phenotypes for that trait Ex. Blood types: A, B, O Ex. Blood types: A, B, O Possible phenotypes: AA, AO, OO, BB, AB, BO Possible phenotypes: AA, AO, OO, BB, AB, BO

Sex-determination Eggs contain 1 X chromosome Eggs contain 1 X chromosome Sperm contain either an X or Y Sperm contain either an X or Y XX = female XX = female XY = male XY = male

Mutations a change or error in the DNA of a cell a change or error in the DNA of a cell can be helpful or harmful or no effect can be helpful or harmful or no effect caused by chemicals, x-rays caused by chemicals, x-rays Environmental impact- skin cancer and sun exposure Environmental impact- skin cancer and sun exposure

Recessive genetic disorders occur when both parents carry the recessive allele occur when both parents carry the recessive allele Example: Example: Cystic fibrosis-build up of thick mucus in lungs and digestive system Cystic fibrosis-build up of thick mucus in lungs and digestive system Sickle cell anemia-clogs blood vessels Sickle cell anemia-clogs blood vessels

Practice Normal blood cells = S Normal blood cells = S Sickle cell =s Sickle cell =s Mom = Ss Mom = Ss Dad = Ss Dad = Ss ______ % chance of ______ % chance of Sickle cell in offspring

Sex-linked disorders An allele inherited on a sex chromosome An allele inherited on a sex chromosome Carried on x chromosome Carried on x chromosome Carrier is if they just have one recessive allele (usually female) Carrier is if they just have one recessive allele (usually female) Ex. Color blindness - cannot see certain colors like red and green Ex. Color blindness - cannot see certain colors like red and green Hemophilia - blood does not clot Hemophilia - blood does not clot More likely in males More likely in males

Practice Color blindness Color blindness X X c X X c X Y

Practice Hemophilia (h) is a recessive disorder to normal blood (H) located on the X chromosome. Hemophilia (h) is a recessive disorder to normal blood (H) located on the X chromosome. X X h X X hXY

Pedigrees A visual tool for tracing a trait through a family A visual tool for tracing a trait through a family Chart used to track which members of a family have a particular trait Chart used to track which members of a family have a particular trait Circles = females Circles = females squares= males squares= males Shaded in = person has the trait Shaded in = person has the trait ½ shaded in = person is a carrier ½ shaded in = person is a carrier

Characteristicdominantrecessive Your trait haircurlystraight hair color brown, black blonde, red eyelasheslongshort dimplesyesno nose Turned up not ear lobes freeattached Hair on middle section of finger yesno frecklesyesno Eye color dark Blue, green gray Tongue roll Can roll Can’t