Genotype, Phenotype Amd Inheritance Flashcards
What is a genotype?
The set of alleles that determines a characteristic. It is the genetic makeup
What is a phenotype?
The observable characteristics
What is genetics the study of?
Inheritance and variation
What is a gene?
A section of DNA on a chromosome that codes for the production of a protein that controls a particular characteristic
What is an allele?
Alternative form of a gene
What does homozygous mean?
2 allele of a gene are the same
What does hemizygous mean?
Only one allele of a gene of the X chromosome
What is a dominant allele?
The allele in a heterozygote that determines the phenotype
What is consanguinity?
A relationship between individuals that share a common ancestor
What s the genetic implication of consanguinity
Offspring are more likely to inherit recessive disorder
What type of inheritance is blood type?
Co-dominance
How is your blood group determined?
Human isoglutamin gene codes for glycoproteins on the surface of red blood cells
What is an autosomal chromosome?
One that is not an allosome (sex chromosome)
For an autosomal recessive disease what is the probability that 2 heterozygous parents will have an affected offspring?
25%
Can autosomal recessive diseases skip generations?
Yes
Why are autosomal dominant diseases rarely found in homozygous state?
Having 2 dominant alleles is usually not viable for life.
What individuals are affected by X linked recessive diseases?
Hemizygous males and homozygous females
Why are x linked recessive diseases more likely in females than males
Females need both copies to be affected whereas males only need one
What type of diseases is Haemophilia A an example of?
X linked recessive
Are males and females equally affected from X linked recessive diseases
No
From whom do you inherit your mitochondria from?
Your mum
What does polygenic mean?
when more than one gene is involved in producing a phenotype
Give an example of a disease with a polygenic inheritance
Albinism
What are linked genes?
Gene that are found on the same chromosome
What is the recombination frequency?
The chance of crossing over occurring between linked genes in a chromosome
What is the recombination frequency dependant on?
The distance between the genes. If gene sare further apart there’s more opportunities for chiasmata to form
What 3 things can you calculate/determine from pedigree diagrams
Recombination frequency, probability of inheritance and inheritance pattern
