Today’s Goal   I can complete a Punnett Square  I can name two people and their contributions to genetics Homework  Study for vocab quiz Friday Warm-up: Define adaptation. 2:001:591:581:571:561:551:541:531:521:511:501:491:481:471:461:451:441:431:421:411:401:391:381:371:361:351:341:331:321:311:301:291:281:271:261:251:241:231:221:211:201:191:181:171:161:151:141:131:121:111:101:091:081:071:061:051:041:031:021:011:000:590:580:570:560:550:540:530:520:510:500:490:480:470:460:450:440:430:420:410:400:390:380:370:360:350:340:330:320:310:300:290:280:270:260:250:240:230:220:210:200:190:180:170:160:150:140:130:120:110:100:090:080:070:060:050:040:030:020:01End2:00

W HAT IS G ENETICS ? Genetics – The study of how heredity information is passed from parents to offspring

W HAT IS G ENETICS ? The Modern Theory of Evolution = Genetics + Darwin’s Theory of Natural Selection

G REGOR M ENDEL Studied inheritance of traits in pea plants Published research shortly after Darwin’s book (but it was in an obscure journal) He received credit for his work in 1900 (15 years after his death) The pea traits he studied later became known as GENES He became the Father of Genetics Law of Dominance (see above)

W HAT IS DNA? Nucleotides contain a nitrogen base 4 different nitrogen bases adenine (A) guanine (G) thymine (T) cytosine (C) Complimentary Strands (A-T) (G-C) DNA = Deoxyribonucleic acid DNA stores information Subunit = nucleotides *3,000,000,000 nitrogen base pairs make you who you are* DNA IS DOUBLE STRANDED DOUBLE HELIX

Your body is made up of cells Each cell in your body contains a nucleus Each nucleus contains pairs of chromosomes Chromosomes contain your DNA sequence A segment of DNA is called a gene A gene codes for a specific trait W HAT IS A G ENE ? Most cells in your body have 46 chromosomes. Sperm and Egg cells have 23 chromosomes.

J AMES W ATSON & F RANCIS C RICK AND R OSALIND F RANKLIN (1953) Discovered the structure of a DNA molecule (double helix) which provided details on genes & how they work Franklin’s x-ray of the DNA molecule – view is above helix, looking down (x pattern is from nucleotide bases)

W HAT IS AN A LLELE ? Most organisms have TWO copies of every gene and chromosome (one from each parent) Alleles are the different forms of a gene for a specific trait Ex: Flowers can be violet or white

W HAT IS AN A LLELE ? Purple is dominant because it “covers up” the white allele in the offspring REMEMBER genes exist as pairs, so often one allele is considered the dominant allele and the other the recessive allele Dominant: trait observed in the first generation when parents that have different traits are bred Given a capital letter symbol (ex: Purple flower= P) Recessive: a trait that reappears in the second generation after disappearing in the first generation when parents with different traits bred Given a lower case letter symbol (ex: White flower= p) Which is the purple allele?

D OMINANT & R ECESSIVE A LLELES Since genes are found in pairs, a pea plant could have the following combinations of alleles for flower color PP = purplePp = purplepp = white The genetic make-up is called the genotype (PP, Pp, or pp) PP and pp is considered homozygous (all one allele type) Pp is considered heterozygous (two different allele types) The outward physical appearance for a gene is called the phenotype (purple or white), which is based on its genotype

P UNNETT S QUARE LETS DO SOME PRACTICE PROBLEMS! P = purple p = white What are the chances of having the white phenotype? What are the chances of carrying the white allele? What is the chance of having a heterozygous genotype? is a diagram that is used to predict an outcome of a particular cross or breeding experiment. ¼ or 25 % ½ or 50 %

TT x tt PRACTICE! Offspring? Tt Tt x Tt 100 % offspring = ____ TT = ____ tt = ____ Tt = ____ 25% 50% 25%

Bb BB bb Bb

Today’s Goal   I can complete a Punnett Square  I can describe how mutations occur Homework  Finish DR How does Evolution occur AND Study for vocab quiz TOMORROW Warm-up: 5 minutes

DNA C ODE AND M UTATIONS The DNA Sequence shows how a species changes over time If a mutation (typo) occurs within the DNA sequence, genes can change causing alleles and traits to change Over time as more mutations accumulate the species changes

Normal DNA (gene): The same sequence is copied to make egg (female) or sperm (male): Let’s say that “AAAGGG” means that you can break down a chemical in milk called phenylalanine A A G A G G A G A G G A

All egg or sperm cells will have the same sequence of “AAAGGG” so all offspring will be able to break down milk Unless something goes wrong when the gene is copied: A Now this egg or sperm cell is carrying a mutation of the gene. Offspring who are born with this gene cannot break down phenylalanine from milk, which causes brain damage when it builds up in the body. A G A G G A A A G G C

T HIS MUTATION HAS LED TO 2 DIFFERENT VARIATIONS WITHIN THE POPULATION : Some babies will be disease free and can break down phenylalanine in milk Some babies will have a disease (called Phenylketonuria) and cannot break down this protein in milk

H UMAN G ENOME (2001) All living things are made of genetic information We have similarities in our DNA to all animals including dogs and fruit flies. The more closely related two species are to each other the more similar their DNA code (genome) Find out your genetic code 23andMe (was $999, now $99) Visit: Other: deCODE; Navigenics