autosomal inheritance · autosomal inheritance bio 40s - kelvin. autosomal traits a trait expressed...
TRANSCRIPT
Autosomal InheritanceBio 40S - Kelvin
Autosomal
Traits
A trait expressed by a gene located on an autosomal chromosome.
22/ 23 Chromosomes are autosomal, the exception being the X/Y sex chromosomes (but more on that later)
Remember:
Segregation and Independent Assortment
Mendel developed two extremely important genetic laws.
Law of Segregation:
The factors of inheritance (genes) are normally paired
BUT are separated or segregated in the formation of gametes.
The gene from each parent splits up, 50/50 chance of either
Law of Independent Assortment:
Each factor’s distribution in the gametes is not related to the
distribution of any other factor.
Genes for hair colour and eye colour arrange separately.
Many unique combinations are thus possible
Remember, the dominant gene masks the expression
of the recessive one.
Like we will see next
Test cross
Sometimes you need to figure out the
genotype of an individual.
You can do this by crossing it with a
homozygous recessive individual.
See the image on the next page as an
explanation ☺
A test cross is used to determine if a parent is homozygous or heterozygous for a dominant trait.
This is done by crossing it with a homozygous recessive individual and observing the results in theoffspring.