Chapter 8.1 Complex Patterns Of Inheritance Flashcards
What is incomplete dominance?
When one allele is only partially dominant.
The phenotype of the heterozygous offspring is a mix of the parents.
What is an example of incomplete dominance?
Red snapdragons (RR) x white snapdragons (WW) = pink snapdragons (RW)
What are codominant alleles?
When both alleles show equally.
What is an example of codominant alleles?
Black chicken x white chicken = speckled chicken
How do you write the allele for feathers that can be black or white?
F with a raised capital B - allele for black feathers
F with a raised capital W - allele for white feathers
What does multiple alleles mean?
Three or more possible alleles determine a trait.
What is an example of multiple alleles?
Rabbit’s coat color - 4 possible coat colors (brownish gray to all white)
How many alleles for each gene can an organism inherit?
2 - one from each parent
What is polygenic inheritance?
When more than one gene affects a trait.
The alleles of different genes work together to produce these traits
What is are examples of polygenic inheritance?
Skin color
Human height
What external / environmental conditions can influence how genes are expressed?
Nutrition
Light
Chemicals
Infectious agents such as bacteria, fungi, parasites and viruses
What are autosomes?
22 pairs of homozygous chromosomes
What is the 23 pair of chromosomes called?
Sex chromosome
What are the possible allele combinations for the sex chromosome?
XX - female
XY - male
What are sex-linked traits?
Traits controlled by genes located on the sex chromosomes
