Summary of Inheritance Patterns Factors That Influence Heredity

Summary of… *Inheritance Patterns *Factors That Influence Heredity (you also need to know about Mendel and genetic disorders)

1. Complete Dominance How many of each are involved with this inheritance pattern? _____ gene(s) _____ alleles(s) _____ genotypes(s) _____ phenotypes(s)

2. Incomplete Dominance How many of each are involved with this inheritance pattern? _____ gene(s) _____ alleles(s) _____ genotypes(s) _____ phenotypes(s)

3. Co-dominance How many of each are involved with this inheritance pattern? _____ gene(s) _____ alleles(s) _____ genotypes(s) _____ phenotypes(s)

4. Multiple alleles How many of each are involved with this inheritance pattern? _____ gene(s) _____ alleles(s) _____ genotypes(s) _____ phenotypes(s)

5. Sex linkage (mostly X-linked, recessive) How many of each are involved with this inheritance pattern? _____ gene(s) _____ alleles(s) _____ genotypes(s) _____ phenotypes(s)

6. Multifactoral / Polygenic How many of each are involved with this inheritance pattern? _____ gene(s) _____ alleles(s) _____ genotypes(s) _____ phenotypes(s)

7. Environmental Effects

8. Gene-gene interactions Gene for baldness masks gene for hair colour. They thought they found the gene for Alzheimer’s…they collected data and not everyone with the Alzheimer’s gene developed Alzheimer’s….

10. Gene linkage Unlinked genes are genes located on different chromosomes , or far apart on the same chromosome. Linkage group A set of genes at different locations on the same chromosome that tend to be inherited together – they`re too close to be separated by crossing over.

Some potential questions… 1) Explain Mendel’s original experiments, including his one-trait and two-trait crosses. Include the laws (dominance, segregation, independent assortment) that came from these experiments. 2) Give 5 reasons Mendel made a good choice with the pea plant. 3) Give 3 reasons that some scientists say that Mendel was very lucky?

Some potential questions… 4) Purple flower colour is dominant over white. Find the possible genotypes when a hybrid crosses with a homozygous recessive plant. REMEMBER: FOLLOW THE 5 STEPS FOR ALL CROSS QUESTIONS!!!!

Some potential questions… 5) Tongue-rolling is dominant over not-rolling and widow’s peak is dominant over straight hair line. Complete a dihybrid cross and state the phenotypes possible.

Some potential questions… 6) A tongue-rolling student’s mother can roll her tongue and his father cannot roll his tongue. Can you be sure of the genotype of the student? Explain.

Some potential questions… 7) In mice, tail length is inherited by incomplete dominance and coat colour by co-dominance. A long tailed, brown mouse and medium tailed white mouse have offspring. What are the possible genotypes and phenotypes of the offspring?

Some potential questions… 8) Blood type is determined by having two of the following three alleles (IA, IB, i). IA is co-dominant to IB and i is recessive to both. A mother with type AB blood and a father with type O blood can have children with which blood types?

Some potential questions… 9) A mother is a carrier for the x-linked hemophilia mutation and a father is normal. What are the chances they will have a child with hemophilia?

Some potential questions… 10) Scientists think they have isolated which gene controls a certain disease, however some people with this gene do not have the disease. What could be happening in this case?

Some potential questions… 11) Scientists notice that the expected ratios for offspring phenotype are not occurring when performing crosses with 2 traits. What could be happening in this case?

Some potential questions… 12) What are BRCA 1 and BRCA 2?

Some potential questions… 13) From what you have learned about inheritance patterns and how they can be affected, explain thoroughly and clearly (in point form) what you think controls how each of these traits are expressed. Note : of course, more than one inheritance pattern can be in effect at the same time! a) fur colour in cats b) human weight c) hitch-hiker’s thumb in humans d) human eye colour e) height of pea plants

Some potential questions… 14) How many unique gametes can be created from the following genotype? Aa Aa. Bb. CCdd. Ee. FFGGhh. Ii Bb. CRCW

Some potential questions… 15 a) The colour in polar bears is determined by multiple alleles – cb (black), cu (blue), cw (white), and cy (yellow). White is dominant to all, black is recessive to all, and blue and yellow are incompletely dominant to each other. Cross cwcu with cycb. What phenotypes can exist in the offspring?

Some potential questions… 15 b) The colour in polar bears is determined by multiple alleles – cb (black), cu (blue), cw (white), and cy (yellow). White is dominant to all, black is recessive to all, and blue and yellow are incompletely dominant to each other. For tail length, long is dominant over short. What phenotypes are possible when a short-tailed black polar bear crosses with a green polar bear who is heterozygous for tail length?

Some potential questions… 16) The lubber grasshopper is a very large grasshopper, and is black with red and yellow stripes. Assume that red stripes are expressed from the homozygous CRCR genotype, yellow stripes from the homozygous CYCY, and both colour stripes are in the heterozygote. There are only 2 options for antenna length in these insects: short (S) and long (s). a) what inheritance pattern governs stripe colour? b) what inheritance pattern governs antenna length? c) what are the expected phenotypes, and in what ratios, in a cross between a red and yellow striped male grasshopper with long anetenna and a yellow-striped female heterozygous for antenna?