1. Biology Week 18
Mendel, Heredity, and Genetics
Chapter 10.1 Pg. 253
Explain why
• some brown eyed
parents may have blue
eyed children, while
• other brown eyed
parents cannot
Gregor Mendel
(1822-1884)
The Father of Genetics
2. Eye color is a trait –
a characteristic
Different forms of the same
that can be trait (gene) are called alleles.
What are two alleles for eye color?
inherited
Traits are coded for by
sections of DNA called
genes
which make up
chromosomes in the nucleus
3. Heredity Genetics
The passing on of
the branch of
characteristics from
parents to offspring biology that
studies heredity
Write observations for each generation.
5. Gamete
A male or female sex cell,
has 1 set of chromosomes,
half of the amount of a normal body cell
A human male A human female A human body
gamete has + gamete has = cell has
1 set of 1 set of 2 sets of
23 chromosomes 23 chromosomes 23 chromosomes
for a total of 46 chromosomes
6. Fertilization
When the male gamete unites with the
female gamete
The first cell is called a
zygote
7. Zygote
The cell which results from the fusing of
male and female gametes, which will
develop into a seed Female gamete
Male gamete
8. Pollination
The transfer of
pollen grains in a
plant from a male
reproductive organ
to a female
reproductive organ
9. Hybrid
The offspring of parents that have
different forms of a trait, such as yellow
or green – which below is a hybrid?
11. Dominant Recessive
Traits that traits that don’t always
appear, can be masked
always appear, by dominant alleles,
CAPITAL LETTER lower case
12.
13. Human Traits: autosomal
1. Shape of face (probably polygenic) Oval dominant, square recessive
2. Cleft in chin No cleft dominant, cleft recessive
3. Hair curl (probably polygenic)
Assume incomplete dominance
Curly: homozygous
Wavy: heterozygous
Straight: homozygous
4. Hairline Widow peak dominant, straight hairline recessive
5. Eyebrow size Broad dominant, slender recessive
6. Eyebrow shape Separated dominant, joined recessive
7. Eyelash length Long dominant, short recessive
8. Dimples Dimples dominant, no dimples recessive
9. Earlobes Free lobe dominant, attached recessive
10. Eye shape Almond dominant, round recessive
11. Freckles Freckles dominant, no freckles recessive
12. Tongue rolling Roller dominant, nonroller recessive
13. Tongue folding Inability dominant, ability recessive
14. Finger mid-digital hair Hair dominant, no hair recessive
15. Hitch-hiker's thumb Straight thumb dominant, hitch-hiker thumb recessive
16. Bent little finger Bent dominant, straight recessive
17. Interlaced fingers Left thumb over right dominant, right over left recessive
18. Hair on back of hand Hair dominant, no hair recessive
19. Tendons of Palmar MuscleTwo tendons dominant, three tendons recessive
14. Law of Segregation
States that every individual has two
alleles of each gene (ex. TT, Tt, or tt) and
when gametes are produced, each gamete
receives one of these alleles
15. Phenotype Genotype
The way an The alleles that
organism looks and an organism has
behaves
18. Law of Independent Assortment
States that
genes for
different traits
are inherited
independently
of each other
19. Punnett Square
Predicts the proportion of genotypes in
the offspring produced by a cross
Aa aa
Aa aa
20. Monohybrid
Dihybrid Cross
Cross
(mono-, "one, single"): (di-, "two"): a cross
a cross involving one involving two
set of alleles, different alleles
ex. Aa x Aa RrYy x RrYy