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Ch 9 Pattern of Inheritance

Cambell Biology Chapter 9 Pattern on Inheritance
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character
An inherited feature that varies from individual to individual.
Trait
one particular variation of a character
Character
an inherited feature that varies from individual to individual
Trait
One particular variation of a character
Monohybrid Cross
a genetic cross involving parents that differ in a single character
Alleles
alternate versions of most human genes
Dominant Allele
If an organism has two non-idential versions of a gene, the one that is express in the organism
Recessive Allele
If an organism has two non-idential versions of a gene, the one that isnot express in the organism
Phenotype
The physical trait of an organism
Genotype
the genetic makeup of an organism
Mendel's view of the mechanism of heredity was radically different from the prevailing view of the time because he saw heredity working through
unchanging (immutable), heritable factors that were contributed by each parent and never mixed
An insect that has the genotype EeGGcc will have the same phenotype as an insect with the genotype _____.
EEGgcc
In an individual of genotype Aa, where are the A and a alleles physically located?
One allele is on one chromosome, and the other is in the same position (locus) on the homologous chromosome.
Human genetic disorders _____.
most often recessive
There are over 100 alleles known for the gene associated with cystic fibrosis. With current technology, it is possible to determine exactly which allele or alleles is/are carried by a person. What is the maximum number of different alleles that any person can carry?
2
Which of the following line or lines of evidence support(s) the chromosome theory of inheritance?
Genes segregate; chromosomes come in pairs.
pangenesis
particles from all the parts of the body are passed to eggs or sperm, and are inherited by offspring at fertilization.
blending hypothesis
1800's, stating that the traits from both parents were mixed, or blended in the offspring, much like paint.
Gregor Mendel
1866, endures as the foundation of the modern science of genetics.
hybrid
the offspring of two different true-breeding parents.
P generation
or parental generation.
F-1 generation
the offspring of the P genteration
homozygous
If the alleles for a trait are both the same
heterozygous
If the alleles for a trait are different,
Mendel's Law of Segregation
Mendel also determined that a sperm or egg carries only one allele for each inherited trait. This is because pairs of alleles separate, or segregate, from each other during the production of gametes in meiosis.
At fertilization, sperm and egg unite, so that both alleles will be present in the offspring.
dihybrid cross
parents differ in two traits.
Mendel's Principle of Independent Assortment
From his evaluation of the offspring, Mendel deduced that each pair of alleles separates, or assorts, independently of all other alleles during the formation of gametes. That is, the distribution of alleles for one trait does not affect the distribution of alleles for other traits.
Autosomal Recessive
Disorder caused by the inheritance of two defective recessive alleles, one from each parent, located on one of the autosomes.
Pedigree:High Frequency both sex
AA or Aa
Autosomal Dominant
Disorder caused by the inheritance ofa single defective dominant allele located on one of the autosomes,
Pedigree: High both sex
X-linked Recessive
Disorder caused by the inheritance of a defective recessive allele located on the X chromosome.
Pedigree: More males
XaXa or XaY
Incomplete Dominance
Incomplete dominance results in an phenotype that is intermediate between the two parents; it looks like the "blending theory" of inheritance.
Type A blood
IAIA and IAi
Type B blood
IBIB and IBi
Type AB blood
IAIB
Type O blood
ii
Multiple Alleles and Co-dominance
Many genes have more than two alleles in the population.
Each allele has an effect; no allele is dominant over another allele.
Pleiotropy
gene's capacity to influence more than one characteristic of gene codes for a particularly critical protein.
Examples include:
Sickle cell disease, which is due to a recessive allele.
Polygenic Inheritance
combined effect of two or more genes on a single phenotypic characteristic. By itself, each gene has a small effect. However, when added together, these effects result in a wide range of phenotypes.
This range can be graphed to provide a "bell curve," or "normal distribution."
Chromosome Theory of Inheritance
It states that genes occupy specific locations (loci) on chromosomes, and that chromosomes (not individual genes) undergo segregation and independent assortment during meiosis.