patterns of in heritance Flashcards
what is a gene?
a section of DNA (base sequence) that codes for a protein
what is an allele?
Variations of a gene
Define genotype
Genetic make-up of an organism
Define phenotype
The observable characteristics of an organism
What is a mutation?
A change in the base sequence of DNA
What are the 3 types of mutagen?
Physical eg. X-rays, UV light, Gamma rays
Chemical eg. Benzopyrene, mustard gas
Biological eg. some viruses, alcohol
What is a deletion chromosome mutation?
Part of a chromosome is excluded during DNA replication
What are inversion chromosome mutations?
A section breaks off, rotates 180 degrees and then rejoin
What is a non disjunction chromosome mutation?
One pair of chromosomes fail to separate, leaving one gamete with an extra chromosome
What is Etoilation?
Plants grow abnormally long and spindly due to lack of light
What is interspecific variation?
Differences between different species
What is intraspecific variation?
differences between individuals of the same species
What is a dominant allele?
The allele that is expressed even if only one is present
What is a recessive allele?
The allele is only expressed if there is no dominant allele present
What does homozygous mean?
BOTH alleles are dominant or recessive
What does heterozygous mean?
Two different alleles (one dominant, one recessive)
What is a locus?
The position of a gene on a chromosome
What is monogenic inheritance?
The inheritance of a characteristic controlled by a single gene.
eg. Wing length in fruit flies
What does pure-breeding mean?
Homozygous
What are recombinant offspring?
Offspring with different combinations of alleles than either parent
What is an autosome?
A chromosome that is not a sex chromosome
When does autosomal linkage occur?
When two or more genes are located on the same autosome. These genes are said to be ‘linked’ or ‘autosomally linked’
How do you calculate the recombination frequency?
)Number of recombinant offspring dived by the total number of offspring) x100
What is a null hypothesis?
There is no significant difference between what we expect and what we observe
Why do we use the chi-squared test?
It measures the size of the difference between the observed and expected results. It helps determine whether the differences are significant or not. It is used to test the null hypothesis
How do you calculate the degree of freedom?
Number of categories - 1
