Transcript 4.1 Living Things Inherit Traits in Patterns

4.1 Living Things Inherit Traits in
Patterns
Mrs. Leos
July 18, 2015
SO FAR……
We have learned that:

Cells contain chromosomes

NOW we will learn about:
How genes for traits are passed from parent to
offspring
 More about Gregor Mendel
 Dominant and recessive alleles

Genetics
The study of gene structure and the
patterns of inheritance of traits from
parent to offspring.
Traits
Inherited Hair color, eye color, blood
type Traits passed from parent to child
Acquired Ability to read, skills learned
Genes
Made of DNA
Control traits that show up in an organism
Sections of the chromosome shown here have
been coloured in. Each section is a piece of
DNA called a gene.
Heredity
Passing of traits (genes) from
parent to offspring
Alleles
alternative forms of the
same gene
Each allele occupies same
position on length of
chromosome
Gene for hair color, allele
could be blonde, brown or
red
Multiple Alleles
A trait is controlled by more than two alleles

Blood Type A&B =AB

Curly hair & straight hair= wavy hair

Brown Eyes & Green Eyes =Hazel eyes

Alleles are considered to be co-dominant
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Co-dominant-both show up
Human Chromosome Number
46
Sex Chromosomes
X-chromosome
Y Chromosome
XX=Girl
XY=Boy
Gregor Mendel- Father of Genetics
Science of how trait are
inherited through alleles
1856 studied garden peas
for height, flower and pod
position, seed shape,
seed color, pod shape,
pod color, flower color
Mendel Success
Mendel figured how
traits were transmitted
from parent to offspring.
He did not know about
DNA, genes or
chromosomes
Phenotype
Actual characteristics that can be
observed
 Physical
trait that show up
Examples:Height, size of feet
How something looks
Pheno=photo
Genotype
The genetic makeup of an
organism, all the genes that an
organism has
Geno=gene
Genotype not always obvious
Principle of Dominant
Dominant Allele -form that appears or
shows up
Covers up weaker form
Recessive Allele –expressed in
phenotype only when two copies of it are
present in the genotype

Form that seems to disappear

Still carried by parent!!
On page 18
Demonstration your understanding
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