Download Slides:Genetics: Scientific study of inheritance

Genetics:
scientific study of heredity
Father of genetics:
Gregor Mendel (1882-1884)
True-breed
vs
Cross-breed
Heredity:
delivery of characteristics from parent to offspring
Fertilization:
sexual reproduction, male and female reproductive
cells join during this process
trait:
specific characteristic of an individual such as seed
color or plant height
hybrid:
offspring of crosses between parents with different
traits also known as heterozygous
gene:
an individual's characteristics are determined by these
factors that are passed from parent to offspring
allele:
different forms of a gene
Dominant / Recessive Traits
Mendel's principle that states that some alleles are dominant and others are
recessive
• Dominant – Represented by a capital letter and masks the recessive allele. T=tall
• Recessive – Represented by a lower case letter and is masked by a dominant allele.
Law of Segregation:
The two alleles for each trait separate during meiosis.
(during the formation of gametes)
gamete:
reproductive cells produced during meiosis
probability:
the likelihood that an event will occur
homozygous:
two identical alleles for a particular gene for example TT or tt
purebred:
Another term meaning
homozygous
heterozygous:
two different alleles for the same gene - for example Tt
phenotype:
physical traits
genotype:
genetic makeup
Punnett square:
use mathematical probability to help predict the genotype and
phenotype combinations in genetic crosses.
Law of Segregation:
Mendel's Law that states the two alleles for a trait
separate during meiosis
Another view of the
Law of Independent Assortment: a random
distribution of alleles occurs during gamete
formation… Genes on separate chromosomes
sort independently during meiosis.
Law of Independent Assortment
Law of Genetic Recombination = 2n
Pea Plants have 7 pairs of chromosomes. What is the possible combinations of
each traits (alleles)?
Chromosome mapping: Determining the distance between genes on a chromosome.
Genetics and Heredity helping to understand Genetic Disorders.
Pedigree: a genetic representation of a family tree that
shows the inheritance of a trait or a disease.
Key to Symbols
codominance:
the phenotypes produced by both alleles are clearly
expressed
incomplete dominance:
cases in which one allele is not completely dominant
over another
multiple allele:
many genes exist in several different forms
polygenic trait:
many traits are produced by the interaction of several genes
Test Cross:
When to use:
Dominant traits & not sure if
genotype is TT or Tt (phenotype
tall).
1.
2.
3.
Sex-Linked
Trait