INTRO LECTURE GENETICS
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Transcript INTRO LECTURE GENETICS
Genetics
Introduction
GREGOR MENDAL:
THE FATHER OF GENETICS
AT 21 YEARS OLD HE
JOINED THE MONASTARY
IN BRUNN, AUSTRIA
HIS JOB WAS TO TEND TO
THE GARDEN
IN 1851, HE ENTERED THE
UNIV. 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.
MENDAL 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
MENDAL ANALYZED
THE DIFFERENCES HE
OBSERVED!
1920s. This shows a close up of the garden
area. It is precisely 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
P generation: Parents
Alleles
F1 generation: Offspring
Alleles
F2 generation: Offspring of
the F1 generation
DOMINANT & RECESSIVE
Dominant trait: The trait seen or observed
Recessive trait: The masked or hidden trait
PUNNETT SQUARE
TOOL USED TO PREDICT THE
PROBABILITY OF A GENETIC CROSS.
CAPITAL LETTER “A” REPRESENTS
DOMINANT ALLELE
Allele: Variation of a Gene
– Gene: Eye color Alleles: Brown, Blue, Hazel
LOWERCASE LETTER “a” REPRESENTS
recessive ALLELE
Important Terms
Genotype: The genetic blueprint
or what the letter (allele)
represents. Letter combinations
– Examples: TT, Tt, tt
Phenotype: How an allele looks;
the physical appearance
– Examples: Tall and short
Important Terms
•Homozygous: An organism with two
alike alleles.
•Homo. Dominant
•2 Capital letters
•Ex. ZZ, BB, FF
•Homozygous Recessive
•2 lower case letters
•Ex. tt, bb, gg
•Heterozygous: An organism with two
different alleles for a trait.
•Heterozygous Dominant: One
capital letter and one lower case
•Ex. Gg, Hh, Zz
Punnett Square
Examples
PUNNETT SQUARE
EXAMPLES