3.1 & 3.2 GENES AND CHROMOSOMES Topic 3 & 10: Genetics

READ & CONSIDER UNDERSTANDINGS – – Genes + Alleles What is a gene? Based on the image above, what is an allele?

Gene A gene is a heritable factor that influences are specific characteristic and occupies a particular locus. All individuals of a species carry the same genes at the same loci on the same chromosome. How then is each individual unique?

Allele Allele: one specific form of a gene, differing form other alleles by one or a few bases only and occupying the same gene locus as other alleles of that gene.

Mutation Mutation – a change in the amount of chemical structure of DNA which results in the alteration or non-production of a protein and the mRNA that codes for it.  Somatic mutation  Germ line mutation

Gene Mutation Gene mutations are changes in the sequence of bases in the DNA of a gene. They are extremely rare because the DNA polymerase has a built-in checking mechanism as it operates.

Sickle Cell Anemia

READ & CONSIDER UNDERSTANDINGS – & – Chromosomes How many chromosomes does a human cell have? Human egg or sperm?

Prokaryotic DNA Prokaryotes have one circular chromosome that is replicated via binary fission. Unique genetic characteristics arise from plasmids containing up to 12 genes. Eukaryote cells do not contain plasmids.

Eukaryotic DNA

Homologous Chromosomes In eukaryotic species genes are carried on different chromosomes. Each parent contributes 23 chromosomes to the offspring, therefore supplying two different alleles of each gene present. Chromosomes containing the same genes (though different alleles) are known as homologous hormones.

Diploid Nuclei Haploid Nuclei Somatic cells are those found throughout the body containing a complete set of DNA (46 chromosomes in humans). Gametes or sex cells contain one chromosome from each homologous pair. The selection is random allowing for high levels of genetic variation. A haploid nuclei contains 23 chromosomes. Somatic Cell vs. Gamete

Karyogram Review Cairns’ technique for measuring chromosome length – page

Chromosome Mutation Chromosome mutation may include a change in the number or sequence of genes. Additional chromosomes may occur (polyploidy) or there may be an alteration in part of the chromosome set.

#1 #2 Karyotype Analysis

#3 #4 Karyotype Analysis

#5 #6 Karyotype Analysis

#7 #8 Karyotype Analysis

#9 #10 Karyotype Analysis

READ & CONSIDER UNDERSTANDINGS – & – Species Specifics What prevents interspecies reproduction?

Genome Scientific NameCommon NameDiploid Chromosomes # Base pairs Homo SapienHuman x 10 6 Pan troglodytesChimpanzee48-- Canis familiarisDog78-- Oryza sativaRice24-- Parascaris equorum Roundworm2-- Escherichia coliBacteria14.6 x 10 6 Drosophila melanogaster Fruit Fly8130 x 10 6 Paris japonicaCanopy plant native to Japan x 10 6

The Human Genome Project

Works Cited "Chromosomes." Genome BC Prenatal Case Study. N.p., n.d. Web. 11 Aug Kaebnik, Gregory E. "Synthetic Chromosomes." Center for Genetics and Society. N.p., 28 Mar Web. 11 Aug Saltsman, Kristie. "Inside the Cell." Cellular Reproduction: Multiplication by Division:. National Institue of General Medical Sciences, 22 Apr Web. 11 Aug Ticator, Statis. "Genetics and Regression Toward the Mean." The Statisticator. N.p., 9 Dec Web. 11 Aug