Slide 1

Slide 2

Goal 3.03 Interpret and predict patterns of inheritance. Let there be PEAS ON EARTH! Let there be PEAS ON EARTH! And let it begin with me! math.uit.no

Slide 3

Modern genetics began in the mid-1800s in an abbey garden, where a monk named Gregor Mendel documented inheritance in peas used good experimental design used mathematical analysis collected data & counted them excellent example of scientific method Gregor Mendel

Slide 4

Pollen transferred from white flower to stigma of purple flower anthers removed all purple flowers result Bred pea plants cross-pollinate true breeding parents raised seed & then observed traits allowed offspring to self-pollinate & observed next generation ? self-pollinate When bred to themselves will always produce organisms with same phenotype. EX. White bred to white always produces white; purple bred to purple always produces purple. When a flower pollinates itself. No new genes are introduced. Mendels work

Slide 5

Mendel collected data for 7 pea traits Each of these traits is represented by a specific allele on a specific chromosome. Allele = genes that determine a specific trait. Flower color Seed color Seed shape Pod color Pod shape Flower location Plant size

Slide 6

2 nd generation 3:1 75% purple-flower peas 75% purple-flower peas 25% white-flower peas Parents 100% 1 st generation (hybrids) 100% purple-flower peas 100% purple-flower peas X true-breeding purple-flower peas true-breeding purple-flower peas true-breeding white-flower peas self-pollinate

Slide 7

Some traits mask others purple & white flower colors are separate traits that do not blend purple x white = light purple purple masked white Dominant allele functional protein affects characteristic masks other alleles recessive allele no noticeable effect allele makes a non-functioning protein homologous chromosomes allele producing functional protein mutant allele malfunctioning protein What did Mendels findings mean?

Slide 8

Difference between how an organism looks & its genetics phenotype Form of the trait that gets expressed what you see genotype An organisms actual alleles Explain Mendels results using dominant & recessive phenotype & genotype F1F1 P X purplewhite all purple Genotype vs. phenotype

Slide 9

Environment effect on genes Phenotype is controlled by both environment & genes Color of Hydrangea flowers is influenced by soil pH Human skin color is influenced by both genetics & environmental conditions Coat color in arctic fox influenced by heat sensitive alleles

Slide 10

Phenotype is a result of both genetics and environment. www.safeandsoundlostandfound.org www.cats-central.com Cold Environment Warm Environment Siamese cats that grow up in a cold environment are darker than those that grow up in a warmer environment.

Slide 11

Inheritance of genes On the chromosomes passed from Mom & Dad to offspring are genes may be same information may be different information eye color (blue or brown?) eye color (blue or brown?)

Slide 12

Remember how Meiosis separates the alleles into sex cells? This separation is called the Law of Segregation.

Slide 13

Effect of genes Genes come in different versions - alleles brown vs. blue eyes brown vs. blonde hair Alleles = different forms of a gene

Slide 14

Homozygous = same Heterozygous = different Homozygous = same Heterozygous = different Homozygous dominant = AA Homozygous recessive = aa Heterozygous = Aa Tt Bb Ww Yy rr RR Aa AB Ss bb Ee BB aa XY

Slide 15

Genes affect how you look X BB bb Bb Where did the blue eyes go??

Slide 16

X Bb bb Bb bb Why did the blue eyes stay??

Slide 17

X Bb BB or Bb bb Where did the blue eyes come from??

Slide 18

Genes come in versions brown vs. blue eye color Alleles (different forms of a gene) Alleles are inherited separately from each parent brown & blue eye colors are separate & do not blend either have brown or blue eyes, not a blend Some alleles mask others brown eye color masked blue

Slide 19

How does this work? eye color (brown?) hair color eye color (blue?) Paired chromosomes have same kind of genes but may be different alleles gene allele

Slide 20

Traits are inherited as separate units 1 from Mom 1 from Dad For each trait, an organism inherits 2 copies of a gene, 1 from each parent a diploid organism inherits 1 set of chromosomes from each parent diploid = 2 sets (copies) of chromosomes homologous chromosomes

Slide 21

Making gametes BB= brown eyes bb= blues eyes Bb= brown eyes BBbbBbBb brown is dominant over blue blue is recessive to brown Remember meiosis! B B b b B b Dominant = can mask others Recessive = can be hidden by others

Slide 22

How do we say it? BB= brown eyes bb= blues eyes Bb= brown eyes 2 of the same alleles Homozygous 2 different Heterozygous BB B B bb b b BbBb B b homozygous dominant homozygous recessive

Slide 23

Punnett squares Bb x Bb male / sperm female / eggs X BB BbBbbb BbBb B b Bb Punnett square practice.

Slide 24

Genetics vs. appearance There can be a difference between how an organism looks & its genetics appearance or trait = phenotype brown eyes vs. blue eyes genetic makeup = genotype BB, Bb, bb 2 people can have the same appearance but have different genetics: BB vs Bb

Slide 25

Genetics vs. appearance eye color (brown) eye color (brown) eye color (blue) eye color (brown) vs. BB B B Bb B b How were these brown eyes made?

Slide 26

Making crosses Can represent alleles as letters flower color alleles P or p true-breeding purple-flower peas PP true-breeding white-flower peas pp PP x pp PpPp F1F1 P X purplewhite all purple

Slide 27

Punnett squares Pp x Pp Pp male / sperm P p female / eggs PP 75% 25% 3:1 25% 50% 25% 1:2:1 % genotype % phenotype PPPpPp PpPppp PpPp PpPp 1 st generation (hybrids) Aaaaah, phenotype & genotype can have different ratios

Slide 28

Any Questions?? www.publispain.com Assignment: Punnett Square Practice Worksheet

Slide 29

2007-2008 Beyond Mendels Laws of Inheritance

Slide 30

Extending Mendelian genetics Mendel worked with a simple system peas are genetically simple most traits are controlled by single gene each gene has only 2 version 1 completely dominant (A) 1 recessive (a) But its usually not that simple!

Slide 31

Incomplete dominance Hybrids have in-between appearance RR = red flowers rr = white flowers Rr = pink flowers make 50% less color RRRrrr RR WW or RR RW or RR

Slide 32

Incomplete dominance true-breeding red flowers true-breeding white flowers X P 100% 100% pink flowers 1 st generation (hybrids) self-pollinate 25% white 2 nd generation 25% red 1:2:1 50% pink

Slide 33

Incomplete dominance RW x RW RW male / sperm R W female / eggs 25% 1:2:1 25% 50% 25% 1:2:1 % genotype % phenotype RR RW WW 25% 50%

Slide 34

Codominance Equal dominance Chickens A black-feathered chicken is crossed with a white- feathered chicken. All of the babies are white with black speckling. Both white and black show up equally. x =

Slide 35

More Codominance x

Slide 36

Multiple Alleles More than one allele to select from. Blood types can be A, B, AB, or O. The alleles to make these types include A, B and i. i is the recessive allele and A and B are both dominant. So to get Type A you must have AA or Ai Type B you must have BB or Bi Type AB you must have AB Type O you must have ii

Slide 37

BLOOD Blood cells have antigens and antibodies. Antigens are tiny receptors on the outside of the blood cell that matches the type. Antibodies are what the cell doesnt like (which is anything different from the type.) Multiple Alleles

Slide 38

Blood Types A A A Type A B B B Type B Type O A B A Type AB B Antigens (none) Anti-B Anti-A none Anti-A and B Multiple Alleles

Slide 39

Genetics of Blood type pheno- type genotype antigen on RBC antibodies in blood donation status AA A or A i type A antigens on surface of RBC anti-B antibodies Receive A or O BBB or B i type B antigens on surface of RBC anti-A antibodies Receive B or O AB both type A & type B antigens on surface of RBC no antibodies universal recipient Oi ii i no antigens on surface of RBC anti-A & anti-B antibodies universal donor Multiple Alleles

Slide 40

One gene : Many effects? The genes that we have covered so far affect only one trait But most genes are affect many traits 1 gene affects more than 1 trait dwarfism (achondroplasia) gigantism (acromegaly)

Slide 41

Acromegaly: Andr the Giant

Slide 42

AA Aa x aa Inheritance pattern of Achondroplasia A a a a Aa A a Aa x Aa Aa aa 50% dwarf:50% normal or 1:1 aa Aa 67% dwarf:33% normal or 2:1 Aa

Slide 43

Many genes : One trait Polygenic inheritance additive effects of many genes humans skin color height weight eye color intelligence behaviors Polygenic = many genes

Slide 44

Human skin color AaBbCc x AaBbCc range of shades most children = intermediate skin color some can be very light & very dark Polygenic = many genes

Slide 45

Albinism Johnny & Edgar Winter albino Africans melanin = universal brown color

Slide 46

OCA1 albinoBianca Knowlton

Slide 47

Coat color in other animals 2 genes: E,e and B,b color (E) or no color (e) how dark color will be: black (B) or brown (b) EB Ebb eeBeebb

Slide 48

SEX and GENES Women & men are very different, but just a few genes create that difference In mammals = 2 sex chromosomes X & Y 2 X chromosomes = female: XX X & Y chromosome = male: XY X only = XO (Turners Syndrome) XY XX

Slide 49

Who you are

Slide 50

Sex-linked traits Sex chromosomes have other genes on them, too especially the X chromosome hemophilia in humans blood doesnt clot Duchenne muscular dystrophy in humans loss of muscle control red-green color blindness see green & red as shades of gray XY XX

Slide 51

XHXH Y male / sperm XHXH XhXh female / eggs XHXHXHXH XHXhXHXh XHYXHYXhYXhY XHXhXHXh XHXH XhXh XHYXHY Y XHXH XHXHXHXH XHYXHY XHXhXHXh XhYXhY sex-linked recessive 2 normal parents, but mother is carrier HH Hh x XHYXHY XHXhXHXh

Slide 52

Slide 53

Most Common Allele Dominant or Recessive Because an allele is dominant does not mean it is better, or it is more common Polydactyly dominant allele Either One!

Slide 54

Polydactyly Recessive allele far more common than dominant only 1 individual out of 500 has more than 5 fingers/toes so 499 out of 500 people are homozygous recessive (aa) the allele for >5 fingers/toes is DOMINANT & the allele for 5 digits is recessive individuals are born with extra fingers or toes

Slide 55

Hound Dog Taylor http://www.last.fm/music/Hound%2BDog%2BTaylor%2B%2526%2Bthe%2BHouse%2BRockers Any Questions? Assignment: Coach Book L17 Textbook pg 180-181 #1-6