GN 301 Module 1: Basic Inheritance

Phenotype

Describes the appearance of an individual for a trait.

Genotypes

genetic information indicated by alphabet abbreviations.

Dominant

The allele that is seen in the individual’s phenotype if an individual has two different alleles for a gene.

Genotype

Describes the alleles (forms of genes) that an individual has for a particular trait.

Cystic fibrosis

________ is inherited in a recessive manner

Y

The egg always carries an X chromosome, but the sperm can either carry an X or ________ chromosome.

XY combination

A(n) ________ creates a male and an XX combination creates a female.

Mutation

serves as a form of adaptation in evolution.

Alleles

the various forms of genes

Define Carrier in terms of cystic fibrosis

Carriers have one copy of the cystic fibrosis allele and one copy of the normal allele

How many chromosomes are in a normal human gamete?

23

Which gamete, the mother’s egg or the father’s sperm, determines the sex of the baby?

The father’s sperm determines the sex of the baby because only sperm can carry a Y chromosome. The egg always carries an X chromosome, but the sperm can either carry an X or Y chromosome. An XY combination creates a male and an XX combination creates a female.

How can the sex of the baby be determined prior to birth?

Using ultrasounds, bloodwork, and choosing sperm likely to have an X or Y chromosome.

Monozygotic twins

are **identical**. 1 sperm and 1 egg join together, and the embryo **divides into 2 fetuses.**

dizygotic twins

are **fraternal**. 2 eggs are fertilized at the same time (each with a different sperm) and **make one fetus each**. Unlike monozygotic twins, dizygotic twins **run in families**.

**Approximately what proportion of your genes do you share with your full sibling?**

50%

**Give the name of a common genetic disorder**

Down Syndrome, Huntington’s Disease, Cystic Fibrosis, Color Blindness, etc.

Other than genetics, what can influence the phenotype of an individual?

The environment can influence phenotype (height, weight, skin color, hair color, etc) beyond genetics.

Mutation

incorrect copy of DNA, or a change in the DNA sequence.

Evolution

The process by which organisms are assumed to have developed and diversified over time from their earlier forms.