Question

multiple choice 1 point
in peas the trait for tall plants is dominant (t) and the trait for short plants is recessive (t). the trait for yellow seed color is dominant (y) and the trait for green seed color is recessive (y). a cross between two plants results in 296 tall yellow plants and 104 tall green plants. which of the following are most likely to be the genotypes of the parents?
ttyy x ttyy
ttyy x ttyy
ttyy x ttyy
ttwx ttw
ttw x ttw

Explanation:

Step1: Analyze the phenotypic ratio

The offspring are 296 tall yellow and 104 tall green. The ratio of yellow to green is approximately \( \frac{296}{104} \approx 3:1 \). This suggests a monohybrid cross for seed color (yellow is dominant, green is recessive), so the parents for seed color should be heterozygous (\( Yy \)). For plant height, all offspring are tall, so at least one parent is homozygous dominant for height (\( TT \)).

Step2: Evaluate each option

• Option 1: \( TTYX \times TTY \) (assuming typo, likely \( TTYy \times TTYy \)) – Wait, no, let's check the options. Wait the options are:
• TTYX TTY (typo? Maybe \( TTYy \times TTYy \))? No, the options given: Let's re - examine. The options are:
• TTYX TTY (maybe \( TTYy \times TTYy \))? Wait, no, the correct approach: The height is all tall, so one or both parents are \( TT \). The seed color ratio is 3:1 (yellow:green), so parents for seed color are \( Yy \times Yy \). Now look at the options: The option \( TtYy\times TTYy \)? Wait, no, the options as per the image (after correcting possible typos): Let's assume the options are about the genotypes. The key is that for height, since all offspring are tall, and for seed color, ratio 3:1. So the parents should have \( TT \) (or \( Tt \) but if \( Tt \), we might get short, but all are tall, so \( TT \) for one parent or both? Wait, no, the offspring are all tall, so the cross for height must be such that no short (tt) is produced. So if one parent is \( TT \) and the other is \( TT \) or \( Tt \). But the seed color ratio is 3:1, so \( Yy\times Yy \). Now looking at the options, the option that fits is \( TtYy\times TTYy \)? Wait, no, the option with \( TtYy\times TTYy \) (but in the options, maybe the correct one is \( TtYy\times TTYy \) but among the given options, let's check the ratio. Wait the first option is \( TTYX TTY \) (invalid), second \( TtYy\times TTY \) (no, the correct one is the option where for height, one is \( TT \) and the other is \( Tt \) (but all offspring are tall, so \( Tt\times TT \) gives all tall) and for seed color, both are \( Yy \). Wait the option \( TtYy\times TTYy \) (assuming the option with \( TtYy \) and \( TTYy \)) – but in the given options, the fourth option (the one with the arrow) is \( TtYy\times TTY \) (maybe \( TTYy \)). Wait, the correct answer is the option where the height genotype gives all tall (so one \( TT \)) and seed color gives 3:1 ratio (so \( Yy\times Yy \)). So the correct option is the one with \( TtYy\times TTYy \) (assuming the option with \( TtYy \) and \( TTYy \), which is the fourth option in the image (the one with the arrow)).

Answer:

The correct option is the fourth one (the one with the arrow, likely \( TtYy\times TTYy \) after correcting typos)