Transcript Mendel & Genetics Power Point

INTRODUCTION TO:
GENETICS
IN 139
Headings
Vocabulary
Important Information
GREGOR MENDEL:
THE FATHER OF GENETICS
• AT 21 YEARS OLD HE
JOINED THE MONASTERY
IN BRUNN, AUSTRIA
• HIS JOB WAS TO TEND TO
THE GARDEN
• IN 1851, HE ENTERED THE
UNIVERSITY OF VIENNA TO
STUDY SCIENCE & MATH
• IN MATH HE LEARNED THE
SUBJECT OF STATISTICS
• STATISTICS HELPED W/HIS
DISCOVERY OF HEREDITY:
– THE TRANSMISSION OF
CHARACTERISTICS FROM
PARENTS TO OFFSPRING.
• MENDEL LATER RETURNED
TO THE MONASTERY AND
TAUGHT HIGH SCHOOL
AND KEPT HIS GARDEN
GOING.
• HE STUDIED MANY TYPES
OF PLANTS BUT HE IS MOST
FAMOUS FOR...
• PISUM SATIVUM, AKA:
– GARDEN PEAS!
• OBSERVATION OF 7
CHARACT. OF PEAS:
– EACH OCCURRED IN
2 CONTRASTING TRAITS)
• USING STATISTICS
MENDEL ANALYZED
THE DIFFERENCES HE
OBSERVED!
1920s. This shows a close up of the garden
area. It is here that Mendel grew his peas.
PLANT CHARACTERISTICS
1.
2.
3.
4.
5.
6.
7.
PLANT HEIGHT--LONG/SHORT
FLOWER POSITION ALONG STEM--AXIAL OR TERMINAL
POD COLOR--GREEN/YELLOW
POD APPEARANCE--INFLATED/ CONSTRICTED
FLOWER COLOR--PURPLE/WHITE
SEED TEXTURE--SMOOTH/WRINKLED
SEED COLOR--GREEN/YELLOW
HIS OBSERVATIONS:
• FLOWER COLOR :
– PURPLE-FLOWERS  PURPLE FLOWER
– PURPLE-FLOWER  WHITE-FLOWERING
• PLANT HEIGHT:
– TALL PLANT SEEDS-->
TALL PLANTS
– TALL PLANT SEEDS-->
SHORT PLANTS
WHY
DO YOU
THINK THIS
HAPPENED?
FLOWER ANATOMY
• ANTHER: MALE REPRODUCTIVE PART
• STIGMA: FEMALE REPRODUCTIVE PART
MENDEL’S METHODS
• HE CONTROLLED THE
EXPERIMENT BY
CHOOSING HOW THE
PLANTS WERE
POLLINATED.
• POLLINATION:
– POLLEN GRAINS FROM
ANTHER TRANSFERRED TO
STIGMA
• SELF-POLLINATION:
– The transfer of pollen from the anther of a flower to
the stigma of the same flower, or to different flowers
on the same plant.
CROSS-POLLINATION:
• INVOLVES
FLOWERS OF 2
SEPARATE
PLANTS
• THE PEA PLANT
THAT MENDEL
STUDIED
REPRODUCED
BY SELFPOLLINATION
WHAT MENDEL DID…
• 1ST: SELF-POLLINATION CAN BE INTERRUPTED
• 2ND: CROSS-POLLINATION PERFORMED.
• HOW THIS IS DONE:
– A) REMOVE THE ANTHER FROM A FLOWER
– B) MANUALLY TRANSFER ANTHER OF A FLOWER ON ONE PLANT TO
THE STIGMA OF A FLOWER ON ANOTHER PLANT
• THIS GAVE MENDEL A CONTROLLED EXPERIMENT.
P1 GENERATION:
– PARENT GENERATION
– MENDEL USED 14 STRAINS FOR EACH OF THE 14 TRAITS HE
OBSERVED
– WHEN PLANTS MATURED HE RECORDED THE NUMBER OF EACH
TYPE OF OFFSPRING PRODUCED BY EACH P1 PLANT
F1 GENERATION:
• GENERATION OF
OFFSPRING
PRODUCED BY THE
P1 PLANT
F2 GENERATION:
–THE PLANTS THAT WERE
PRODUCED BY THE F1
GENERATION OF PLANTS
• FIRST FILIAL
GENERATION
• THESE THEN SELFPOLLINATED AND
COLLECTED SEEDS
F2 generation
HOW COULD THESE TESTS
HELP US UNDERSTAND
HOW WE INHERIT OUR
TRAITS?
DOMINANT & RECESSIVE
• MENDEL CALLED THE
TALL HEIGHT OF THE
PLANT DOMINANT
– B/C IT HID/MASKED OR
DOMINATED THE
SHORT HEIGHT
•THE SHORT PLANT WAS
CALLED RECESSIVE
•HOW DOES THIS RELATE
TO US?
PUNNETT SQUARE
• TOOL USED TO PREDICT THE RESULTS IN
GENETICS
• CAPITAL LETTER “A” REPRESENTS
DOMINANT ALLELE
• LOWERCASE LETTER
“a” REPRESENTS
recessive ALLELE
• LET’S DRAW AN
ALLELE ON YOUR
LEFT PAGE
GENOTYPE & PHENOTYPE
• GENOTYPE: THE GENETIC BLUEPRINT OR
WHAT THE LETTER (ALLELE) REPRESENTS:
– “T”
– “t”
• PHENOTYPE: IS HOW THE ALLELE LOOKS
– “T” = TALL PLANT
– “t” = short PLANT
• HOMOZYGOUS: AN ORGANISM W/2 ALIKE
ALLELES FOR A TRAIT THAT ARE EXACTLY
THE SAME (tt OR TT)
• HETEROZYGOUS: AN ORGANISM THAT HAS
2 DIFFERENT ALLELES FOR A TRAIT (Tt)
PUNNETT
SQUARE
EXAMPLES