Inherited change Flashcards
What does codominant mean?
Alleles which are both expressed in the phenotype (if they occur together)
What is the genotype?
The combination of alleles expressed by an organism
What is a phenotype?
The observable characteristics of an organism due to their genotype and environment
What is an example of co-dominance?
Flower colour in snap dragons, the can be red (CrCr), white (CwCw) or pink (CrCw)
What allele exist for blood groups and how do they interact?
Ia, Ib and Io for blood group A, B and O, A and B exist in co-dominance, causing AB blood group, O is reccesive to both
What combination of alleles is used in the test cross?
Homozygous dominant + homozygous recessive produces all dominant alleles, heterozygous and homozygous recessive produces half and half
What is the difference between blood group?
A or B antigen is displayed on the membrane of red blood cells, the O group displays neither
Which sex chromosome carries more alleles?
The Y chromosome is shorter than the X chromosome, so it carries fewer alleles
How is colour vision affected by gender?
The allele for colour vision is only on the X chromosome, colour blindness is recessive therefore boys, who only have one X chromosome are more likely to have the colour blindess
What are some other inheritance sex linked?
Haemophilia
What is a Barr Body?
Supercoiled inactivated X chromosome, which occurs early in females embryonic development
What are dihybrid crosses?
Consideration of two characteristics at the same time
If the genotype is RrYy, what are the gametes produced?
RY, Ry, rY, ry
What is an autosome?
A non-sex chromosome
What is autosomal linkage?
When two genes are located on sex chromosomes, so are inherited today