Karyotype = picture or pattern of chromosomes arranged in homologous pairs & organized by size (See fig. 14-1 p. 341)
Humans have 46 chromosomes
2 of these are sex chromosomes
XX = female XY = male
The other 44 chromosomes are known as autosomes
To study inheritance, biologists use pedigree charts
Shows relationships within a family
Pedigree studies are often used to track genetic disorders in a family.
Many traits are strongly influenced by environmental factors (ex: height,personality). The degree to which traits depend on genetics is called HERITABILITY
Our complete set of genetic info , Includes tens of thousands of genes
Genes are mapped to chromosomes.
Used to determine how traits or diseases are inherited.
Example: BRCA1 is located on chromosome 17, it is associated with risk of breast cancer.
Controlled by 3 alleles - A, B, O
A and B are codominant
O is recessive to both A and B
The blood type is the phenotype
|Blood Type||Genotype||Can Donate to...||
Can Receive from...
|AA, AO||A or AB||A or O|
|BB, BO||B or AB||B or O|
A or B or AB
A, B, AB, O
Tay - Sachs disease recessive
*Also gives resistance to malaria
Blood types (A and B are codominant)