Transcript Genetic Variation

Genetic Variation
7th Grade
Investigation 9: Genetic Variation
Populations & Ecosystems
Inheritance
• Inheritance: Passing genetic information
from one generation to the next.
• Gregor Mendel: famous scientics who
studied pea plants and determined genes are
inherited from parents.
Animal Cell
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Importance of Cells
• Everything (living) is made of cells and that is
where the information describing “you”
resides.
• Cells have many smaller structures called
organelles, that perform functions essential
to life.
• The nucleus of our cells contains our genetic
information.
Inside the Nucleus of A
Cell
• Inside the nucleus is the inheritance
messenger, DNA.
• DNA molecules are huge, containing
millions of atoms.
• In order for DNA to fit inside the
nucleus, they are coiled into structures
called Chromosomes.
Chromosomes
• Chromosomes: the structures that
carry the message of inheritance.
• Chromosomes always come in pairs.
• On every chromosome is an allele.
Allele
• Allele: variations of genes that
determine the traits in organisms.
• BIG IDEA: The two corresponding
alleles on two paired chromosomes
constitute a gene.
Genes
• A gene (two alleles working together)
controls a trait.
– Helps determine things like eye color,
etc…
Genotype
• Genotype: An organisms particular
combination of alleles.
– Genotypes lists the paired alleles that are
particular to that organism
Dominant & Recessive
• Dominant Alleles: more-influential
alleles. Represented by a capital letter.
• Recessive Allele: Less-influential
alleles. Represented by a lower case
letter.
• Ex: A or a
Phenotype
• Phenotype: the traits produced by the
genotype; the expression of genes.
– Ex: What a larkey looks like.
Phenotype
• Every organism has its unique
genotype, composed on paired
chromosomes.
• Those genes produce unique traits in
those organisms.
• The traits that the genotype produces
results in the organisms phenotype.