Mendelian Genetics Flashcards
What is true breeding?
When offspring look like their parents
What is an allele?
A variation of a gene like eye color.
What is a dominant allele?
The allele that is expressed
What is a recessive allele?
The allele that is masked
What does it mean to be homozygous?
To have to of the same allele. Can be homozygous dominant or recessive
What does it mean to be heterozygous?
To have 1 of each allele. The dominant generally shows
What is a genotype?
The genetic make up. The genotype indicates the phenotype
What is the phenotype?
The physical appearance. You cannot know a genotype from a phenotype
What are Mendel’s laws of hereditary?
1) law of segregation-alleles separate during gamete production
2) law of independent assortment-alleles separate independently
What are Mendel’s 4 principles of inheritance?
1) genes have alternate forms
2) for each characteristic you have two alleles
3) an egg or sperm only has one allele
4) when the 2 alleles are different, one is shown and the other masked
What is a test cross?
Used to determine a genotype. Cross the unknown genotype with a homozygous recessive. If any offspring show a recessive trait the unknown was heterozygous
How does probability play a role?
Rule of multiplication-chance of two independent events at the same time
Rule of addition-chance of one event or another
What is a dihybrid cross?
A two trait cross (use the FOIL method)
What is intermediate inheritance?
When neither of the two alleles for the same gene dominate each other. Like white and red flowers making pink
What is co-dominance?
When both alleles are fully expressed. Like a roan horse
What is epistasis?
When an unrelated or independent gene will over ride another to produce an unexpected genotype. Like yellow labs
What is pleiotrophy?
When one gene displays many phenotypes
What is complementary interaction?
When two alleles or genes interact to cause a new phenotype that neither is capable of showing
What is polygenic?
When many genes contribute to one phenotype. Like skin color
What is a sex linked trait? (X)
Females are carriers of x linked traits. The trait is more often found in men because they only have one X chromosome
What is a Barr body?
It’s a dormant chromosome in all female somatic cells. They are random and independent. Prevents increased expression of genes of chromosome. Like calico cats
What are P1, F1, and F2?
Parental, first filial, and second filial generations
What are recombinants?
Offspring that do not look like their parents. Occurs because of the crossing over of chromosomes
