Exploring Genetics

Unit C. Basic Principles of Agricultural/Horticultural Science

Problem Area 3. Understanding Cells, Genetics, and Reproduction

Next Generation Science/Common Core Standards Addressed!

MS‐LS2‐4. Construct an argument supported by empirical evidence that changes to physical or biological components of an ecosystem affect populations. [Clarification Statement: Emphasis is on recognizing patterns in data and making warranted inferences about changes in populations, and on evaluating empirical evidence supporting arguments about changes to ecosystems.]

RST.6‐8.1 Cite specific textual evidence to support analysis of science and technical texts. (MS-LS1-6),(MS-LS2-1),(MS-LS2-4)

RST.6‐8.2 Determine the central ideas or conclusions of a text; provide an accurate summary of the text distinct from prior knowledge or opinions.

6.RP.A.3 Summarize numerical data sets in relation to their context. (MS-LS2-2)

Agricultue, Food and Natural Resource Standards Addressed!

BS.01. NCAE Standard: Assess factors that have influenced the evolution of biotechnology in agriculture (e.g., historical events, societal trends, ethical and legal implications, etc.).

BS.01.01. Investigate and explain the relationship between past, current and emerging applications of biotechnology in agriculture (e.g., major innovators, historical developments, potential applications of biotechnology, etc.).

Sample Measurement: The following sample measurement strands are provided to guide the development of measurable activities (at different levels of proficiency) to assess students’ attainment of knowledge and skills related to the above performance indicator. The topics represented by each strand are not all-encompassing.

BS.01.01.01.a. Research and summarize theevolution of biotechnology in agriculture.

Bell Work!

Explain how genotype and phenotype are different.

Describe how the gender of offspring is determined.

Distinguish between qualitative and quantitative inheritance

Terms:

Gamete

Zygote

Chromosome

Genotype

Phenotype

Allele

Heterozygous

Homozygous

Dominant

Recessive

Offspring

Trait

What determines the gender of offspring?

The study of genetics is concerned with the transfer of traits.

Gregor Mendel discovered that these traits are inherited through units called genes.

Genes were found in pairs and half of the inherited traits come from the father and half from the mother.

GametesSex cells! Known as the sperm from the male and egg from the female,

Meet in fertilization and mix genetic material from both.

The resulting zygote contains genes from both mother and father, and displays characteristics from both.

Determination of the sex

Depends on the sex chromosomes. Male sex chromosomes are either X or Y. The male makes sex determination as all eggs from female receive an X chromosome. Female zygote will have two X

chromosomes (XX) while a male zygote will have one X and one Y chromosome (XY).

The same thing may happen with color!

Black Bull! Black Cow!

Red Calf?

How are genotype and phenotype different?

Genotype is the actual genetic code.

It controls physical and performance traits.

The genotype of an organism cannot be changed by environmental factors.

Phenotype

Is the organism’s physical or outward appearance.

This is the part of the genotype the organism expresses or shows.

In some instances, phenotype may be altered by the organism’s environment.

Homozygous

A homozygous organism is one having similar alleles or genes on the DNA molecule for a particular trait.

Heterozygous

A heterozygous organism is one having different alleles for a particular trait.

What is the difference between qualitative and quantitative traits?

Qualitative traits are traits controlled only by a single pair of genes and cannot be altered by the environment.

These traits most easily show how genes are inherited. An example is coat color.

Quantitative traits

Traits controlled by several pairs of genes. These traits are expressed across a range.These traits can also be altered by environment. Examples include rate of gain,

growth rate, backfat depth, etc.

Expression of Traits

Not all traits contained within an organism are expressed.

Dominant traits cover up or mask the alleles for recessive traits.

Expression of Traits

In some organisms there are cases of codominance of traits in which both dominant and recessive genes are expressed.Incomplete dominance may also occur. This happens when a blending of

the allele pair is expressed.

The End!