3.4 Flashcards
What was Gregor Mendels experiment?
He crossed plants with different characteristics to determine if they produced predicable patterns in the offspring
What is a genotype?
Symbolic representation of the pair of alleles that an organism has
What is a phenotype
The characteristic or trait of an organism
What is a dominant allele
An allele that has the same effect on the phenotype whether it is paired with the same allele or a different allele; always expressed in the phenotype.
What is a Recessive allele?
An allele that affects the phenotype only when paired with another recessive allele
What are co-dominant alleles?
Pairs of alleles that both affect the phenotype when present. (A black chicken and a white chicken ,asking a speckled chicken)
What is the locus?
The position of a gene on a chromosome
What does homozygous mean?
Having two identical alleles of a gene (maternal and paternal version of the gene is identical
What does heterozygous mean?
Having two different alleles of a gene (maternal and paternal version of the gene is different)
Hat does carrier mean?
An individual who has a recessive allele of a gene that does not display that phenotype
What is a text cross?
Testing a suspected heterozygous by crossing it with a known homozygous recessive individual.
What is the F1 generation?
The first generation produced by a cross
What is a F2 generation?
The second first generation produced by crossing members of the F1 generation
What is an autosomal recessive disease?
A genetic syndrome resulting from the inheritance of two recessive alleles for a gene found on one of the first 22 pairs of chromosomes
Why are genetic diseases rare?
Because many people with genetic diseases don’t have the opportunity to reproduce and pass on the recessive alleles
What is a sex linked gene?
A gene found on one of the sex chromosomes
What happens if a male inherited a recessive x linked trait
There is nothing on the Y to counteract it so they will have the disease
Which gender can be carriers of recessive sex linked traits?
Women because they have two X chromosomes, men cannot be carriers because they only inherit one sllele for certain traits
What is a mutagen?
Something that causes changes to DNA
